The only way to do this is if you have it for PC using console commands. Even using console commands to change your wife/husband you will mess up the game.
The only thing you can change on your face in skyrim is... EVERYTHING. you cant change gender, weight, or race. but you can change scars, hair, color, and paint.
Not in vanilla Skyrim, but with the Succubus Race mod, yes.
Unfortunately, once the player has chosen and confirmed their race, name, etc. it can't be changed on any console except for the PC.
Yes! No matter what your race, you can get married
if you mean with your wife you can't.
I don't think you can on Xbox 360, It might be possible with a load of hacking through your computer or something.
Use a Khajiit, they are good at sneaking.
Khajiit
Kajiit NOT REDGUARD
Dark Elf, Khajit or Argonian
Yes. Argonia's have an advantage in that.
Yes, Lydia is one of the potential spouses.