1. It should be the stylevar content_background_color, but that will change the color for the postbit background also, I believe. So, you may want to write some custom css kinda like:
HTML Code:
.userprof_content { background-color: pink; }
2. Not sure what you mean. The background stays the same for me when I hover over the albums. We would need a link to a page on your site that we can see in order to see what is up.
3. I believe you would need to modify the actually php code in group.php to change that.