MrDeflok I can't answer all of those questions but I can tell you two of them.
4. Citizen Siege does not take place on oddworld, that being said, the oddworld games take place on oddworld. I'm not sure, but I think that Citizen Siege takes place on Earth.
7.
http://oddworldlibrary.net/archives/togg/ does have some good pictures of alot of the characters.