Following the live chat, SimGuru Karsky has answered some additional questions on the Sims 3 Forum.
One thing I've been keen to know more is about Vamps, and if it will affect the current ones…
Answer â€“ The vampires are the same Sim type as the ones in Late Night with additional visual options and new ways to intimidate, so you won’t see two varieties in your game if you already own Late Night. And of course a big difference is that you can now just create vampires and change the way they look right from the start in Create A Sim.
He's also confirmed that supernatural offspring will have a 50/50 chance of taking after either parent, rather than being hybrids, and the population control will be a checkbox which, it turned off, will stop the game generating any more of that type of creature. It won't remove any that are already in-game, and you can still create them either in game or in CAS.
The full post can be found here
His blog also has more background info too.