1) No rules and play with aging off. I have only 1 save but it is copied at different stages.
2) I don't know how many household I have. There are at least 2 families in each world. I create a new household whenever there is a new world or when new gameplay calls for it ( like building a tiny house did ).
3) Have played rotational since S2.
4) I use all worlds. My favorite worlds are Forgotten Hollow and Glimmerbrook.
5) No drawbacks
6) I usually start with Y.A.F., but not always. My favorite household is a vampire family of 5 ( the mom is the only non-vamp.) with 3 extra kids in 2 other households.