Cross-posting. Tsk.Tsk.
I'll answer the other ones for people who might ask the same questions...
1. Mailman (and other mail list packages) and SpamAssassin both install fine on SME. There are how-to's and in some cases rpm's around for both.
2. Yes, both PHP and MySql are part of the package. PHPNuke, PostNuke, XOOPS, MyNuke, etc... all install and work fine on SME. Once again there are how-to's kicking around for most of this stuff.
Good luck!