7
1. No. Any domain will do, so long as you define that domain in mainfile.php as your Virtual Directory for XOOPS.
2. Why would you want to do a thing like that? ;)
3. Yes, but you have to hack that yourself. Do a search on XOOPS.org for "multisites hack" for a how-to.
4. Not a clue. Luckily, XOOPS doesn't use CGI scripts.
5. No. You can customize XOOPS to have whatever you want and to exclude anything you don't like.
6. Check the other thread where you asked the same question
7. That one's up to you. You can get free domains like yoursite.dyndns.org or something like that, or you can go purchase a cheap domain name...
http://www.godaddy.com has a sale on .com names right now ($6.95 I believe for a year).
Hope that helped!