I wonder if the developers realize that vampires are corpse...? Where they lust would get from, they are supposed to be cold impotents
To answer your question. Vampires are different within this setting. Unless I misunderstood Jill explanation to Valeria. Valeria admittedly being the lovable bitch she is, continuing to interrupt her. It's explained that Vampires are living beings. Leaning more into being mutants compared to your traditional, undead vampires.
Now, I don't know the canon status of this game compared to the events of Darkness Revenge, but I remember Lauren or someone telling Jill about vampires in great detail after she became one. Assuming Jill is meant to be the exact same and it isn't just a fun easter egg that she showed to Valeria. Darkness Revenge would be your best bet for the lore and what the dev is going for with his vampires.
There obviously might be some changes or improvements. Since this game takes place a hundred or so years after that one.