Actually I realized that my original answer is based in the households I'm playing this week. My family households (descendants of the founding sim) are semi-realistic. Even the vampires and spellcasters in the family have jobs and kids and at least half normal lives, and the rest of the family is non-occult. But I also have extra occult households that are not realistic at all.
In general, any supernatural/extraterrestrial thing that comes with the packs I own exists in my sims' world, but the family is basically about family play. And they all age at the same rate and die of whatever causes the game might choose, including old age, and they have to earn their money and grades and most of them have to do their own cleaning (unless they have magic or money), they have real world hobbies and all that stuff. The non-family households are much more "Anything Goes." But they are a smaller percentage of the households in my rotation.