This is an amazing, wonderful piece of work. I'm sitting here with tears in my eyes at the end of it (brought on by what happens at the end of the story, not just by the fact that it has ended).
I love how flawed and trying-to-figure-things-out all your characters are; love the flesh you've given to all of them, and LOVE LOVE LOVE the magical theory involved. (Magical theory is a total kink of mine, and you've done wonders with it!) The backstory to the 'peds is fantastic, as well.
I really do hope more folks find time to read this (and comment!) soon. It's astonishingly good.