I have a HUGE long response coming.
Stay tuned. Or ... come back in about an hour and I'll have it ready.
These questions are preceded by a lot of assumptions. If one of these is wrong, please correct me.
You're going to get a LOT of different answers to ALL of these questions, Bart. Even in this one thread. About two dozen Christians REGULARLY haunt this one sub-forumd, and so two dozen answers are likely.
Here are mine:
I assume that your god is all loving.
He is a God of love, yes. The Bible even directly says that "God is love."
I assume that he is also all powerful.
Yes. I opt for "all-powerful" position on God myself.
I assume that your belief system dictates that he created everything.
Yes. I also subscribe to that notion. (But I also believe the Earth is a HECK of a lot older than a mere 6,000 years.

)
Then comes the concept of heaven and hell.
This can get very divisive. This concept is where various disagreements can sneak in. But I'll try and give you my own take.
From what I understand, Satan was once an angel,
We don't know that for certain. The likelihood is VERY good that he was an angel. The Bible never overtly says it, but the assumption is reasonable because of the following
(I'm going to spend over 50% of this entire post just discussing whether or not Satan is or isn't an angel--sorry! I just love talking about angels!!!
I promise that I do get to your others questions later in this same post! I have here NINE points of argument about Satan being an angel.):
1) He's certainly not God.
2) He's definitely not a man.
(And if he's neither God nor a man, that doesn't leave too much else, unless you wanna start including aliens in your cosmology.)
3) He seems to have either an unusually long life-span, or else an eternal life span --considering how many places in the Bible he keeps popping up. I'm going to dwell on this one point here for a bit.
The "serpent" appears in the Book of Genesis in the Garden of Eden where he deceived Adam and Eve. And then we see mention of some character in the Book of Revelations Chapter 12 who is called by FOUR names all in one verse.
And there was war in heaven. Michael and his angels fought against the dragon, and the dragon and his angels fought back. But he was not strong enough, and they lost their place in heaven. The great dragon was hurled down—that ancient serpent called the devil, or Satan, who leads the whole world astray. He was hurled to the earth, and his angels with him.
FOUR names, so there is NO mistaking his identity. And then after that verse names all four names, it also goes on to describe him as being the one "who leads the whole world astray," so now there is NO mistaking his purpose. He's a bad guy, no doubt about it.
Of those four names, one is "that anceint serpent." And this is deemed to be a critical link between this "dragon" guy found in Revelations, and the serpent we read about all the way back in the Garden of Eden-- seen as the strongest proof-text in the argument that "the dragon" in Revelations and "the serpent" in Eden, are one and the same. Also, he's called an "ancient" serpent, so he's very very old.
Michael is also very very old. Michael is found in Daniel (around 500 to 600 BC) and he's later found in this Revelations account (and there's no knowing at all when that Reverlations account might have taken place--soem scholars say it took place either in the ancient past, or in the distant future). Gabriel is also very very old. Gabriel is found in Daniel (500 to 600 BC) and Gabriel later appears in the Gospels (around 4 BC). So angels in general are deemed to be creatures of very long life spans, possibly of immortal life spans. So if Satan is an angel, he's one very old old OLD creature.
4) The Archangle Michael does battle with him TWICE in the Bible (and a third time if you want to count the battle in the Book of Daniel, but I don't count that one myself) and Michael won both times (Michael also won in Daniel, but again I don't count that one). And so it's reasonable to assume that if Michael is an angel, and if Michael did battle with this guy called "the Devil," then perhaps the Devil is an angel himself. (BTW--the two battles that I do count are the Revelations one I already cited, and then an odd little battle that's briefly referred to in a blink-and-you'll-miss-it passage in Jude-- concerning the Devil trying to take the dead body of Moses, and Michael stopping him from that corpse-robbing crime.)
5) There is an obscure reference that's draped in lots of poetic imagery in Isaiah Chapter 14 concerning some character who looks to be a human king. And that pasasge is deemed by quite a few scholars as being what's called a "dual-reference" verse. It refers to a human king--BUT it's possibe that it MIGHT simultaneously refer to the Devil as well, naming pride as his sin. It's also the one and only passage where we get the name "Lucifer" from since this king is called "Lucifer" here. Meanwhile, there's ANOTHER such passage in Ezekiel Chaper 28 that also refers to a human king, but is likewise deemed a "dual-referecne" verse, speaking not just of the fall of that human king, but also of the fall of Satan. It speaks in sad tones of a past glory he once held as a "cherub" which is a type of an angel, and specifically, an angel appointed to stand guard in the closest possible spot right beside the throne of God itself--so a cherub is an angel of prominence. And this passage speaks of his having lost that prominence.
6) Getting specificaly into the whole "cherub" thing .... The Ark of the Coveneant--yeah--the gold box from "Raiders of the Lost Ark"--had two golden angel figurines mounted on top of it facing each other (those two golden angels were specifically called "cherubs") to represent the type/species of angel that was allowed to stand THAT close to the glory of God itself. And it's important to note that those two golden figurines were most likely KNEELING while atop that gold box, and if not kneeling they were at the very least BOWING. And their two sets of wings were extended upward and foreward. And above their wings was where a small glowing cloud would appear, and that cloud was the presence of God, and from that glowing cloud the voice of God would speak. The two golden angels had their eyes cast downward from the cloud, possibly bowing if not actually kneeling--because that is what angels do, they bow and kneel before God (in the Book of revelations they are CONSTANTLY kneeling before God). And then several hundred years later, when Solomon had the Temple built, he commissioned his gold smiths to fashion TWO MORE golden angels to adorn the inside of the Temple. However, those two new angels were NOT tiny little figurines capable of sitting on your car's dashboard. They were HUGE TOWERING statues. And they both stood 30 feet tall. And they also were most likely KNEELING. (When one entered the Temple and saw those two huge massive kneeling angels, one would hopefully get a clue from that imagery: if the mighty and powerful creatures known as ANGELS would choose to kneel before God, then we probably should as well. And not just ANY angels, but the oo-ah-wow type of angels called CHERUBIM.)
But ... my orignal point is to focus on the cherubim .....
.... If it turns out that Satan was indeed once from the species of angel called cherubim (the singular is cherub, the plural is cherubim), then he was of the highest order or angels (possibly the most powerful order), charged with the highest and most honorable duty: to stand in God's presence right beside his throne--and he foresook that position. He gave it up. He fell from a great height and from a position of great honor.
On other matters .....
7) The Book of Job presents a curious appearance by Satan. In that book, a group of beings called "the Sons of God" show up, and Satan is in their midst. It is believed that "the Sons of God" are in fact angels. So if Satan is with these guys called "the Sons of God" then perhaps he is an angel also.
8) Back in Genesis Chapter 3, right after Adam and Eve get expelled from Eden, the way back into the garden is suddenly set under a security watch: a group of cherubim armed with "flaming swords" is charged with guard detail outside the garden entrance (this is the very first mention of angels in the Bible). It's possibe those cherubim were not just trying to keep Adam and Eve from getting back in, but possibly also to keep the serpent (Satan??) from getting back in. I mean, think abot it! He could probably have done a lot of damage with some stolen fruit! So, if Cherubim are the most powerful species of angel, and if Satan is a Cherub, then only Cherubim woud be strong enough to keep him out. Thus were Cherubim given the task of guard detail.
9) Again, in Genesis, but jumping ahead to Chapter 6, the "Sons of God" show up and there's a curiously strange reference to them taking wives from amongst human women and producing children by them. And the children that resulted were not truly human. These half-human/half-angel offspring seemed to posess extrardinary abilities, and eventually an entire race of them walked the Earth, existing as a competing race alongside humankind. This one passage has caused a LOT of division amongst Christians (and Jews and Muslims too--so we're talking about over 80% of the population of the planet here in a dither over this one passage!). It's not one too many clergy like to talk about. It's clearly in the Bible, and yet what should we make of it? If you really wanna irritate a clergyman, ask him about this passage. He'll probably walk away from you. Or give you a creative way of dismsising it as unimportant or merely poetic and not literal.
And on the subject of angels producing offspring, I am of the opinion that angels are physical creatures with physical bodies, but that we do not understand all of their physical abilities. They can physically sit in a physical chair, and eat physical food if it's offered to them, and even clean up the dishes when they're done. They can also evidently change their bodies in some metaphysical way so that they can walk right through that same chair like it was thin air. And after pulling that nifty trick, turn around and sit in the same chair again. The Bible clearly shows us they can appear and disapear at will, possiby walk through solid walls, can fly, and even eat human food. How they do this, I don't know. But I believe they can and do. I am also of the opinion that they are limited by both time and space. Only God can transcend time and space. Angels (in my opinion) cannot. (We'd be in a REAL mess if Satan had the ability to travel through time!)
Other questions arise: do angels have gender (male and female) or are they genderless? Do angels have sex? Do they get married and have children? And do their children grow up to be mommy and daddy angels also? And if you cross-breed an angel with a human, what do you get? Jesus said that the angels neither marry nor are they given in marriage. So no marriage and presumably no sex and no offspring. But ... maybe they still have gender, and yet are simply forbidden to use/express it in a sexual way. Why? I don't know. Why make an entire race of beings capable of sex and forbid them to have sex? I don't know. (Why make a tree that produces perfectly good fruit and forbid anyone from eating from it?) It wold seem that marriage is reserved for humans. Marriage is something very sacred that has been denied of the angels. And it would seem that the one instance in Genesis where a group of angels went ahead and entered marriage anyhow resulted in something rather disastrous: an unauthorized species. And it is believed (because of another book found OUTSIDE the Bible which ALMOST got included in the Bible--a book called Enoch) that the flood of Noah was necessary because the world was fillled with the wickedness of these unauthorized species, and they had to be exterminated. Possibly not just them but maybe all kinds of other species were suddenly crawling around the planet the likes of which God never authorized. Modern-day speculations by some scholars include talk of genetic experimentation by the fallen angels in the pre-flood era to produce sinsiter species that God never intended. CS Lewis and JRR Tolkien also subscribed to the idea that certain species that exist to this day are not species God ever intended, and their fantasy writings bear out those notions. (Tolkien had a particularly nasty disdain for spiders.)
Our resident AW poster who goes by the screen name
III, and his real name is Jay Young, has written and published several fantasy novels about this exact scenario of the angels having children via human women. I haven't read his novels (yet) so I don't know which scenario he goes after (and there are hundreds of scenarios possible), but I hope to one day read his work. I suspect he'll be chiming in at any moment now.
and--dissatisfied with God--he left heaven and founded hell. (Pardon my ignorance of the correct terminology throughout this post, by the way.)
Umm .... Hell is (to my understanding) a place in which the Devil is NOT YET DWELLING. Hell is a place of punishment that he will one day be sent to .... but not yet. For now, he's bound here upon the Earth. The place called Hell is "reserved for the Devil and his angels." And in Revelations, we read that he will be cast into Hell at the end of all things ... but not yet. Until then, he's HERE on the Earth.
What he actually did was found "the Kingdom of Satan" which is an invisible kingdom here on the Earth--in fact, one of satan's names in the Bible is "the prince of this world." The Bible speaks of battles waged by the good guys against "the principalities and the powers and the spiritual forces of wickedness in the Heavenly realms." And --to further emphasize that point-- another one of Satan's names is the Bible is "the prince of the powers of the air" and another name is "the Lord of those who fly." So this imagery of Satan and his minions flitting about through the air is repeated strongly in the scriptures. Getting back to the Book of Daniel, the angel Gabriel was sent by God to fly down to the earth and deliver a message to the prophet Danile. However, Gabriel was intercepted and delayed for ten days by someone called "the Prince of Persia." It's believed that ths Prince of Persia guy was in fact another angel--an EVIL angel in the employment of Satan. And Gabriel and the Prince of Persia were locked in some kind of immortal combat for ten whole days, and finally Michael had to come and rescue Gabriel. So when Gabriel finally showed up ten days late, he was practically apologizing to Daniel and was explaining the delay. That whole incident with the Prince of Persia is used to suggest that certain geographic regions of he Earth fall subject to the jurisdiction of certain angles--good and bad angels. And that there are territorial disputes between them from time to time--turf wars--border disputes between the good guys and the bad guys.
My question regarding Heaven and Hell is this: if one of God's angels could grow dissatisfied with heaven, does it not follow that normal people could as well?
I believe it would indeed follow that such might be the case.
One of the questions raised concerning angels is: after Satan and his angels all fell, did other similar rebellions by other angels also follow? Some scholars believe that after that one instance of rebellion, the angels who remained faithful to God (evidently they were called "Michael and his angels") were granted a special measure of "keeping grace" to prevent them from falling at all. So they are now eternally saved no matter what. As for us humans ... the Book of Revelations promises that when we get to Heaven there will be "no more crying, no more pain, no more death" and that a permanancy of happiness awaits us. So ... why would we WANT to fall away? And even then .. it can be reasoned that if the angels got that special measure of "keeping grace" then perhaps we will also.
::EDITED TO ADD::
If normal people can grow tired of heaven, doesn't this imply something bad about God?
I would say no. It simply shows that God took a huge risk when he chose to make creatures with a free will, completely distinct from his own will. Angels have distinct wills, and some of them rebelled. Humans have distinct wills, and ALL of them rebelled. And the sad consequences of this risk is something God already foresaw before he even went ahead with the creation. He knew mankind would be a failure. He knew we would rebel. And he knew he had to save us. And yet he went ahead and made us anyhow--with our rebellious free wills and everything. This is why Jesus is called "the Lamb of God who was slain from the foundations of the world." God knew even back then that Jesus would have to die. Free will is a tricky thing. Tolkien did a great exploration of free will in The Silmarillion when he explained the origins of the Dwarves. It's an awesome theological concept he raised via that fable of the Dwarves' creation. I highly suggest you read it.It's mind-expanding.
Meanwhile, my favorite line from the movie Bruce Almighty was when Morgan Freeman was trying to explain to Jim Carrey the rules about being God and how you can't violate people's free wills. Jim Carrey asked: "But how do you get people to love you without violating their free will?" Morgan Freeman smiled and said "Welcome to my world."
The edicts of Christianity dictate that in order to get into heaven, one must accept Christ as their savior, yes? God is All Powerful and All Loving, though--why must there be a stipulation on his love?
'Tain't a terrible stipulation, dear.
Also, there are many people all over the world who have never heard of Jesus or God. There are also people who grow up hearing of Jesus and God, but associating them with something evil because they grow up in a rival religion. If accepting Christ as your personal savior is the only way into heaven, how can God be All Loving or All Powerful if there are people in this world who have never heard of God or Jesus--or worse, if they are brought up by their parents to be prejudiced against both.
Some Christians believe that the grace of God is broad enough to make special allowances for those who never heard of Jesus. Others say "Nope, Jesus is the only way and so those who never heard of him perish and that's final." I'm not as draconian as that myself.
One of the most difficult questions for any clergyman to try and answer is: "Why did God take my little girl?" And the next question is even worse: "Is my little girl in Heaven?" A common answer from medieval days (as bourne out by the tiny angel scultpures and angel paitings from Medieval and Rennaissance art) is that little babies become tiny angels in Heaven. While that's a comforting thought, it has no basis in the Bible. However, the Bible DOES say in more than one place that little children simply do not know right from wrong, and that God seeks mercy for such instacnes. Even Jesus mentioned angels who stand before the throne of God and who plead mercy for little chidlren. So I believe that special grace is afforded to those who simply do not know. I can't explain what the nature of that grace is, nor how the practical outcome of such grace manifests itself. But I believe God is merciful beyond what we can comprehend.
*braces for assault from those who disagree*
I promised my girlfriend I would open my mind to the idea of God if someone could answer these questions for me in a way that makes sense. That said, these are not loaded questions and I am not here looking to start trouble.
I do not pretend to know the mind of God. I try to "work out my own salvation with fear and trembling." I have very personal reasons for believing God is real. I'm sure your girlfriend does also. It's all very subjective and very personal. All this other stuff in my post is just years of study. The relationship-with-God part is more the personal stuff that I can't explain. When I'm all done talking about angels and theories and theological extrapolations, and when you ask me to get personal about me and God, I usually can't. It's VERY personal stuff. It's beyond mere theory for me, it's faith.