Terry, I like the idea of your writing Lex as a good guy. You've changed the personalities of the other key characters like Lana and Clark and to some extent Lois in this alt-universe, and so there's a consistency in making Lex a good guy. It would complete the symmetry, so to speak.
Also, I think it might be a fanfic first to have Lois fall in love with a good guy who is not Clark Kent.
Now, to make Tank happy, you could turn Jimmy into a villain.
carol