[Hall of Famer]

umm I am a little bit confused at what you mean by the MA system. Are you referring to the myadopts.php? I do believe you can edit the layout so long as you know basic css, with or without PHP skills. The navlinks can be edited directly in ACP, while sidebar links have to be edited in a more complicated fashion. I can show you how to do it, if you dont mind modifying php code.

Well there is no simple way to 'install' a theme. The custom themes released in the Themes/Templates subforums are not compatible with new version(they do not support dropdown menu), while the themes you can find from css layout sides need heavy modification too. Id suggest looking into the main theme's css and start from there by editing colors, images, font and other stuff. This is assuming you know basic css. If you dont know css, PM people like Nyxi, Silverdragontears and Gloometh for help.