While this discussion seems to have gone off on a tangent, I want to address the OP's post.
I am Choctaw Native American and I see issues with the story you propose:
1. Native American spirits are not "magic." They are religious figures no different than God, Jesus, Mother Mary, and saints are to Christians. If you wouldn't use major Christian religious figures as magic entities in your book, then why would you use Hopi religious figures that way? Keep in mind that portrayals of Native religions as magic and superstition have resulted in the devaluing of our sacred sites and led to the government routinely destroying those sites even to this day. Right now, sacred burial grounds are being destroyed to construct Trump's border wall. During Obama's administration, sacred burial grounds were destroyed to make way for the Dakota Access Pipeline. And before that... I think you get it. We need pop culture to take our religions seriously and end the "magic" stereotype because movies, books, and TV are where most people get their information on our religions. If that information is incorrect, there's little that Natives can do to counter the misconceptions. We make up such a small minority that our voices speaking out aren't heard.
2. You state that magic came about in the 1970s and that Natives became powerful because their rituals were more intact. Native cultures weren't intact in the '70s and they're not now. Forced assimilation and genocide have been destroying our cultures since 1492. Entire tribes have been wiped out and others have completely lost their traditional religions and languages. 130 million Indigenous Americans were killed to make way for Europeans. That amount of death and destruction can't happen without causing permanent damage to cultures and their religious practices.
3. An Algonquin person interacting with a spirit of another tribe--and one a thousand miles away--makes no sense. I don't pray to spirits of other tribes because they're not part of my culture, just like how a Christian doesn't pray to Hindu gods.
4. Languages are tricky if you don't speak them. I don't know how different Cree is from English, but my native Choctaw language is structured in a way that is completely different from English. If someone who didn't speak Choctaw tried to fake their way through it by translating word-by-word, the overall sentence would make no sense. For instance, to say "I am a young Choctaw woman" in Choctaw, you have to structure the sentence as "Choctaw woman young I am" (Chahta ohoyo himitta sia). We also have different verbs depending on the number of people performing an action. One person "going" is "ia," two people going is "ittiachi," and three or more people going is "ilhkoli." Again, I don't speak Cree, but if you're not taking structural differences, conjugation, etc. into consideration, you're not going to be able to fake your way through it.
I had no issues with the character's traumatic backstory, though. And I disagree with those who say that you can't write characters of races/ethnicities you don't belong to. In my view, writing non-ownvoices characters only goes wrong when you take someone else's culture and shape/alter it to fit your story or your views. You do that here with the Hopi spirit and the Algonquin character stepping out of her own culture to contract with that spirit. You may also be doing that with the languages you include but don't know how to speak. For these reasons, I find this story problematic.
I'm glad that you came here to ask about these issues before you went any further with your book. Many people (*cough* J.K. Rowling *cough*) tend to just write whatever they want about Native religions without consideration for the offense they cause to actual Natives. You're already better than they are.