1) In Tabula Rasa this is what customs colors are set to by default:

set custom_foreground_element = "userpic_border";
set custom_background_element = "userpic_background";

so it looks like this is what you want.

If you look at function FriendsPage::print_stylesheets() in http://www.dreamwidth.org/customize/advanced/layersource?id=550&fmt=html you'll see what this does and what the other pre-set options are.

If you're not happy with any of this you can use set custom_colors_template, which is explained in the Core layer I've linked to above. If you need more help don't hesitate to tell me so.