Hmm, that seems to make sense. Or maybe, again, its just more 'logic' from the SoS crew.

I assumed that was what was meant by the sisters 'sharing their victims', yes. That's what tipped Justine off, I think. Otherwise its a bit of a coincidence, him living with one and shagging the other. Although if he met Sarah through Time-of-your-life...unless they both came along, and Other!Succubus! just lied about having lived with him for a few months. But I assume so yes.