For genres, how about "Young Adult"? It would be nice if we could distinguish it from "Children's" stories.
  It would also be nice if we could pick more than one, like in a check box format (it could lead to stupid people clicking all of them because they want to be found, but that's unlikely in such a closed community), but maybe you could just add mixed options, like "Children's Fantasy", "Fantasy Horror" (to distinguish vampires from regular slashers) or the like.
  More genres could be "Biography/Autobiography", "Rant", "Historical Fiction" and that's all I can come up with right now.

  For styles, what about a "Script"? "Monologue"? An "Essay"? A "Personal Narrative" (autobiographical short story of a pivotal time in the author's life, usually with the power of hindsight in the subtext)?