Every vampire thing has its own lore. I would say that it's probably pretty similar to FK. (And yeah, I mainly watched it for LaCroix, too.) Usually in this kind of scenario, the sire is owed loyalty, etc. Now, this being said, Mick did kill Coraline(sp?), so it can't be too ingrained into them. Josef is certainly old, but Coraline and her 6 brothers are supposed to be the really old bad-ass vampires.

As to the territorial fight I mentioned, Mick was welcomed into that family after they had returned him to a human state, which implies that despite the fact that Josef changed him back, he's still considered part of their clan. It should be interesting to see if there's going to be a fight for him (provided there's a S2).