GMT time: I don't know when you saw that GMT time was 10:01 PM, but I think you should just try the settings. Looking at the time you posted that, I'd say GMT-4 should work. Just try it
The buddy list is a quick way of seeing who's online, and an easy way of sending PMs to those people. You can enter names of members in your user cp, the Buddy/Ignore list section. People who are ignored cannot send PMs to you.
The reputation system allows members to quickly judge whether a member is helpful or not. If the square is grey, you have a neutral reputation. A green square indicates a positive reputation, while a red square indicates a negative one. Many squares indicate a very positive or very negative reputation.
Currently, only elite members, super moderators and administrators can hand out reputation points. You can see for which post you were given points, and optionally the comment that was provided. You cannot see who gave you a reputation, unless the person who gave you the reputation included his/her name in the comment.