As you have not linked your blog to your username in your forum profile or supplied the url we cannot see the front page of your blog and determine what your "front page" problem is.
Forum profile - Look at the top right hand corner of the forum page where it says "view your profile" and click on it if you wish to complete it.
Changing themes => Dashboard => Presentation => Themes ( find the one you like and click it). No data or images will be lost regardless of how many times you change themes. However, some themes do not have widgets and others do. Some have more than one sidebar so you may have to re-arrange them.
Re-arranging widgets => Dashboard => Presentation => Sidebar widgets (drag the widgets you want out of the Available Widgets box and drop them into the Sidebar box (or boxes) in the locations of your choice then click "Save Changes".
Avatars - There is a time delay for avatar display. Your avatar will first be seen here in the forum. Thereafter it will appear whenever you post on the forum, leave a comment on another blog or on your own. It will also appear on the wordpress.com tag pages with your posts in the category/tag pages that you assigned to the posts. It will not appear elsewhere. However, you can choose to place it in a text widget manually and place it in your sidebar.
As you are new this thread may be helpful for reference purposes http://en.forums.wordpress.com/topic.php?id=5257&page&replies=19