I am still struggling with all of this, as I feel I don't have a "universe" for my POTO fic. They are just scattered vignettes. So now, as I am trying to write some Persian/Christine (impossible) for a Christmas present, I am wondering: which characters am I writing? Do I start from "the beginning"? Or do I take what I've written and develop those characters in a new situation? I don't have the answers you seek, because I don't think I've gotten that far yet.