no to all your questions, there is the fighters guild, the thieves guild, the mages guild and the dark brotherhood. There are many factions though but they are only, like, trophies, they do nothing and you only the only reason they exist is for 1 quest like the prison feeding job is for a quest as an excuse to visit prisoners however you do not even get payed. ALSO, go here
http://www.uesp.net/wiki/Oblivion:Oblivi… it has all the information about the game there is including available mods, patches, fixes, factions, guilds, and all quests there is and much, much more.