This is a bit of a late answer to your question but I'll answer it in the hopes it will be helpful to anyone else who stumbles across it!
1. The food at Caius is great- obviously there are a few meals that are a bit awful, but plenty of good meals too. I think it used to be awful in the past but Caius made some major improvements as you mentioned. It is definitely an outdated stereotype that they have bad food.
2. I havent lived in these two sites but I've heard it's not as bad as it's made out to be. Unfortunately if you are bottom of the ballot then you probably will end up in these places. Truthfully being at the bottom of the ballot at most colleges will give you some sh*t accomodation.
3. From what I've heard from others, Caius used to be full of posh w*nkers and very private school lad-culturey but since caius got new people in charge in admissions there has been a rise in state school students and in general a change in the kind of people admitted. My year group is very chill and down-to-earth on the whole.