No problem.

having a few aristocratic families would certainly be a way to both stabilize and destabilize such a society.

For simplicity's sake, we'd also recommend primarily sticking to a single universe of vampires. That will save a hell of a lot on the lorebuilding. The art of worldbuilding is not something that is quickly done. Its easier when you base it on the "real" world, but still quite a lot of work.