JKSManga
Vampires are actually my favorite fantasy creatures, so i hope he still has the weakness of sunlight and another weakness, the inability or disgust for eating human food. This novel and The Rise of Vampires are the only good vampire stories out there. So I'm really happy you're writing it and hope you don't drop. And please keep all original novel's favorite character development to the minimum, it's just filler and just makes the story boring, well for me at least.
Let me just put this out there. Quinn, as a vampire, should be extremely cunning and charming, using others for his own survival. My idea for peter would be to pretty much use him, kind of like how DIO used others. If you look at the way DIO used humans, he charmed them with a simple glance and used them for his purpose as simple marionettes. Layla will probably become a vampire, or atleast a half-ling, Vorden will probably become one too, but don't forget that the vampire way is a hierarchy. Quinn will be the head, Layla and Vorden are going to be under Quinn simply because he would be the original vampire. Also, if Quinn does use peter, it would probably be like livestock or a puppet, he could even make him something like a thrall or ghoul.