How about this: if the scion or changeling uses any of his supernatural powers for an attack, the catch is met. If not, then not.
Can two Changelings have a Changeling kid or would it be a human? That'd be an interesting twist... and does that mean they are more human or more fae?Well, it depends on why they're having a kid. Remember, the choice can be made based on actions rather than deliberate choice - so two changelings deciding to settle down and have a family? Poof, all are human. One of them doing this for future power & influence, or maybe even just immediate gratification? Poof, that one's fae, and the kid is a changeling. Grey area? They could still be changelings, and the kid would be too, imo. It's all wibbley wobbley; go with whatever makes the most sense for the plot, or see if any PCs want to spend fate points on declarations.
My argument on Ghouls is that they breed true, so that means they're more natural than unnatural (I'll give that in our game they qualify as Outsiders), if that makes sense to folks. That's why I brought up the question in the first place.I'm not sold on the idea of ghouls as Outsiders personally. I think they're more along the lines of necromantically twisted* human stock. That said, if ghouls are created / powered by Outsiders in your setting, I'd simply have them invoke their high concept for effect to meet a catch of "Outsider" for a scene. That fate point would come from a limited supply the NPCs earn, not from the bottomless GM supply.
Can two Changelings have a Changeling kid or would it be a human? That'd be an interesting twist... and does that mean they are more human or more fae?Sure, why not? I don't see changeling status as being percentage based...it's about the Choice. So even a 1/4 fae might end up choosing full fae status at some point.
Switching gears for a moment, where does this "Ghouls = Outsider Scion" stuff originate from? I can't recall anything that would indicate that they have Outsider blood or are otherwise related to Outsiders, but perhaps I'm missing a reference somewhere. I know there is the theory presented in OW that 'mundane' Ghouls are Scions of Uber-Ghouls, but beyond that I'm coming up blank. I almost got the impression from what sqlcowboy was saying that "Outsider" was being used as a stand-in for "supernatural" (otherwise I have no idea what "breeding true" has to do with it).That's mostly fan-theory, that the Uber-ghouls are Outsiders, because of how Harry (and Lash) handled the conflict at the end of White Night