I think the victim is either killed/ripped apart or stolen away, depending on whose version you read (The Hunt can also give gifts to those who offer them respect). I think for Blaine, the destruction will be a positive thing, going with death=transformation (so yes, you're right); it's necessary. It could be the final destruction of his Persona that he requires to start seeing himself (and letting himself be seen). If he's taken by the Hunt, to either join them or be stuck as their game forever (i.e., he returns to Dalton) that's a stagnant sort of immortality. Blaine cannot grow from that--Dalton is a trap--so he must let them destroy him, so he can die [yet] again metaphorically.

He also needs to metaphorically behead, stab through the heart, or drown Sebastian, so I'm glad to hear Grant is returning. (Or, alternatively, actually become friends with him in a way that is not threatening, but this seems unlikely? IDK, I'm still a little uncertain here. Sebastian is Shadow so must be defeated or integrated.)

I'll see what I can manage in terms of a more general overview of Jungian stuff. It might take a day or two. And thank you, I'm glad my thoughts have some clarity! :)