A 12 guage Coach would be a pretty fair choice for either situation, the only accomodation would be the load.
As stated, you can use slugs for bear, and around the house, #6 shot would discourage the heck outta a home intruder without the overpenetration of more serious loads. Double 00 buckshot is a very good self defense load, and will kill a person quite well if that is your intention, but will have more wall penetration capability.
Probably one of the better choice for a self-defense weapon if someone doesnt want to spend the time to become an experienced shooter, but no matter, whoever is planning to be able to use it, they must be familiar with it and have had some practice.
dago