There is not much you can do to make your avatar picture prominent while displaying your nickname, Op.
You are fine with fancy sign with your nick alone? Bitcointalk requirement for avatars are really low...
No. Not with my username alone. Mix something more and be creative
Mix some figures to make it unique in whole bitcointalk. And if anyone uses yellow color in excess amount then his/her entry will not be counted because I hate yellow color.
You can still use but don't use in big amount