The kid characters of today won’t be on TV forever, so we might never see little Sally Draper all grown up, or any of the children on Parenthood become their adult selves. And yet it seems we don’t need to, because most of the kids on shows right now already have adulthood dopplegängers, grown-ups who share some of their quirks and seem to be their ghosts of Christmases future. So who are you gonna be when you grow up, Sally Draper? Oh, we already know …