Yep, I've got two dead parents in my YA series, but they do make a ghostly appearance at the end of book 1 because they are responsible for laying down clues and riddles to get my teen group through an alternate world.
Other concerns that I think are relative to the industry is the danger, or the caution that should be used in writing outside your cultural box. On the one hand they covet cultural, race, ethnic and religious diversity. I'm all for that, and I incorporate it. Yet I get a bit wobbly when I read about these huge firestorms about new authors (supposedly) committing huge racist blunders, prompting those authors to pull their books. The presence of a reviewer is just as powerful as any other text on an Amazon page, or anywhere else for that matter. How easy is it to torpedo an author? A glass of wine and a temper can do it. I guess that's the reason for mentioning "sensitivity" readers in the RD article. So publishing YA today might be a wee tougher in that regard.
I did write A YA fantasy series. I don't have a huge message to convey. I didn't want to hit my reader over the head with a profound theme. For some reason I thought that teens, or even the cross-over adult readers, didn't want to hear a lecture or preachment about social mores, and that they might be tired of seeing it. Themes about real life are great and vital, but I picked up almost all of my life's lessons from Leave it to Beaver and they stayed with me. I read Divergent, The Hunger Games and the Potter books, and I did see messages there. I do have subtle ones, but I just wanted to write a kick-ass escapism with a hell's bells ride. I just hope there's room for me.