For me it was quite a bit different from first year halls. I can't quite tell from your post what you want, but I found that people did try to make friends so that they'd have someone at home that they'd get on with, but weren't at all bothered about making 'new best friends' like freshers do, because they'd already done that.
Everyone in my flat (six people) was hard working and not too out going. Only one of us went to clubs (but with course-mates), and half of us liked to drink (we always said that we should go to the pub together, but never got round to it). We already had friendship groups from our course, so we never spent too much time together, but four of us would always chat to each other when in the kitchen (we barely saw the other two).
One of them was on my course, so I got on with her and saw her the most (we always cooked at the same time); it might have been a bit boring if it wasn't for that to be honest.