The most important comment here was “all set-ups work.” They do. For the most part, 18-year-old human beings are really good at adapting to different living conditions, no matter what they think in advance. Yes, there’s conflict sometimes, but usually they can work it out.
(Years ago) D was in an old, disfavored dorm slightly off campus, and more importantly off the campus maps, so that nobody who didn’t live there or have a close friend there knew exactly where it was. This generated lots of folklore about dormcest and lack of sociability, none of which had any predicate in reality. The dorm was all tiny singles, basically 5 boys and 5 girls to a hallway, with two small single-sex bathrooms on the hall. It had a number of nice common areas, and a huge institutional kitchen the kids could use. The woman in the room directly across the hall left after one week, and a woman who had become instant friends with my daughter moved in. So it was a great set-up for them, where they were roommates if they kept their doors open, but could close them for privacy. The friendship somewhat petered out as the year went on, and for the next year my daughter moved to an off-campus apartment with a gay boy she had known since fourth grade and some friends of his. She was very social, and spent most of her time out of her dorm or apartment in any event, but she always preferred to live with quiet, neat people – her living space was a place of calm and order, not a place for partying.
S, at the same college, chose the largest, most social dorm, then an impressive but dilapidated building far from the center of campus. He had a traditional double, in a room large enough to have been a forced triple had the third kid ever showed up, with a small bathroom in the room. He and his roommate never meshed well, and after a while they basically ignored one another. My son learned that he didn’t really like living in the most social dorm, although he was a pretty social person himself, but that he actually appreciated having some distance between where he lived and where he worked. He didn’t bond with a lot of people on his floor, but two women there pulled him into a club team the first week of college that became one of his main extracurricular activities, and he has remained friends with them and the roommate of one of them years later. He spent a lot of time with friends in other dorms. His future fiancee was on a different floor in the same dorm, but although they were classroom friends they didn’t socialize together back then. He couldn’t wait to move into an off-campus apartment the next year, in a small building (8 apartments, 28 people total) where almost everyone was involved with the university theater, his other main extracurricular. It was like a theme house.
This was at a college where the general pattern is freshmen and sophomores live in college housing and juniors and seniors move off campus into the surrounding student ghetto. Freshmen are required to live in a dorm absent unusual circumstances. A few students live on campus all four years, usually spending the last as an RA. It was not the norm, but not at all uncommon, for kids to move off campus after one year. I had lived in a dorm with essentially the same group of friends all through college, and loved it, so I was surprised at how well non-dorm living suited my kids. (And it was meaningfully less expensive than the dorms, for much, much nicer space.)