LATE PAGE! sorry!!!
there are a few jokes about Scout's lack of origin here and there in the comic, characters relating theories they've heard, but i think i like the false origins better than i think i'd actually like revealing a concrete origin. besides the unknowable mystery being integral to who Scout is, i'm not sure revealing an origin would make her a better character.
i think the uncertainty about Scout's origin, her not knowing what she is or where her powers came from, is as important as the certainty any other superhero has. Scout's mystery is the same as Spider-Man's radioactive spider.