To add to/correct the above :P
1) I'd have to agree. If you want to avoid noise go for a hill college as the bailey does get loud at night. I think if you avoid the college bar you'll avoid most of the internal noise. There'll obviously be rowdy people at whatever college you go to but whether you avoid them or not is just the luck of the draw with who you're put with.
2) Mildert and Butler have absolutely no shared rooms. Collingwood has a few but they're apparently rarely used nowadays, same with Hild Bede. Actually Hild Bede is a relatively quiet college too I'd imagine, it's not near any other colleges, though it is relatively far away from the science site though I'm not sure if that affects you. Also the bar isn't in the same building as any accomodation I think. Most other colleges have sharing rooms, Bailey colleges more so than hill.
3) I have to agree with the above, all areas are relatively safe.
4) I can't really add to the above either, though I've heard that Hild Bede has very mixed accomodation. The room one of my former housemates was in in her 1st year wasn't the nicest of rooms but I've heard other rooms are better and she was in one of the worst blocks.
Basically...I'd probably recommend Mildert or Hild Bede, depending on how bothered you are about distance/location, type of building (HB older, Mildert more modern) and quality of room. Possibly Butler if you don't mind being self-catered, if you want to be self catered then definitely Butler!