I've already made around 10 summons that seem to work for 10 MMM creatures, and I integrated them to the leveledlists (some of them do require a lot of magica though, so you wont see a normal conjurer summoning a balrog, just the bosses of the guardians of oblivion might do that) but I dont know how to make NPC sell them, I want to make Traven sell spells but it didn't work (I did AI "offers services" package and stuff) then I added some of my spells to "gaspar stegine" (well I just add them to his spells window maybe I'm missing something) and he still sells the same than allways, the OOO ones includes of course...

Also, how can I modify how attributes and skills work, you know the multipliers and "knockout chances" and everything...

Thanks, Sorry for my bad english

Ok for your first question go here this will tell you how to fix your first problem.
http://cs.elderscrolls.com/constwiki/index.php/Dynamically_Adding_Spells_to_Merchants
Now I don't understand your second question, If you do a search on the wiki for example "modify Skills" that may take you to where you want to be or it may not. Just do a search on the WIKI the box is on the left hand side. Most of your questions will be answered, then if you need more help come back and you can ask again. Good luck on your mod.