A prefab hutch or cage is too small for even one rabbit in my opinion. I have 2 rabbits in a 4'x8' pen and they get time out of it every day; I plan to add a second story in the future to part of it for more space. X pens, basically a wire playpen, are easy to set up and expandable if you can't create a sufficient space all at once, but if you have dogs you might want something a bit tougher. tThe little prefab huts aren't too bad to put in the pen, at least ours has been fine so far and both bunnies use it. They're just as happy with a cardboard box that has doors cut in it though. Ideally the rabbit should be able to hop 4 times across the pen from what I remember.
Rabbits are social animals so yes, it's better to have a friend.
