Re: first things first
1) Is not a bp issue. It’s a css theme issue. You are welcome to modify the distributed theme or use any theme that you’d like.
To address 2 and 3 we need to know what version of bp you are using, what version wpmu to start with. Things are pretty busy round here lately. Topics scroll off the front page radar within 12-24 hrs. Can you post links to the 2 and 3 topics?