A rabbit can be free roam as long as your place is rabbit-proof. I would not advise going full, free roam until you have had ample time with your rabbit while supervising in the free-roam space to see what nooks, crannies, and tendencies the rabbit may have.
Wick is free-roam 24/7 in my small apartment, and from observations, I know never to leave anything on the coffee table while I’m gone, close the bathroom door, etc.. If your place is able to be rabbit-friendly in entirety, the more room the better; however, if you it’s too risky due to furniture elevations, spacing of walls (rabbits are pretty good at discerning distances, but if they fall in a gap behind something, they may get trapped), than only free-roam when you’re around, and put them in a secure X-pen when you’re not there.
As everyone said, there is special considerations if you want two rabbits. The bonding process is quite complex and takes a lot of time, dedication, and space. A solo rabbit is an option, though not the preference. Wick is a solo bun, but I’ve learned by having him that he prefers minimal attention during the day, so him being alone is not an issue. If the shelter you are looking at mentions a rabbit who may do better in a more quiet, mellow environment, perhaps that could be a route. Most rabbits sleep from 8AM to 3PM anyways. That’s actually Wick’s bed time, daily.
Are you living with family, roommates, or anyone else? I consider it a requirement that at least one other person (preferably all those who may have a chance to interact with the rabbit(s)) is familiar with rabbit care as well, so when you’re gone for trips, vacations, or just gone overnight for some reason, you have a reliable other person to take care of your pet.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.