Does anyone have experience with 1) allowing someone to rent/reside in an extra room in your house or
2) neighbors with additional occupants (renters?) in their home as well as the additional cars that has to be parked on the street? What are the city requirements (if any)?
You'll want to get some legal advice on this one.
If it's your house, I don't think there are any laws against renting out a room, but as Joe noted, the renter has rights that you have to respect.
Also check with the city, but I don't think there are any regulations as to parking any extra cars on the street.
A friend of mine had 5 kids, and sort of adopted another. There's about a 10 year spread between them, and they lived at home into their 20's. Between him, his wife, and the kids there were 8 cars in the driveway and on the street. Neighbors weren't happy, but there were no rules against it.
My nephew is going through it with a neighbor in LA. The guy has 5 cars and he moves them around to stay within the law regarding how long they can be parked in one spot.