Re: slight model edits
 

If you can't change the eye color how about changing the area around the eye instead? See no one can see the color of the eye unless it is in a cut scene anyway. If you changed the skin color around the eye to reflect a scar or burn mark that would be more noticeable anyway.

Re: slight model edits
 

Maybe, however, I could just recolor both eyes and say the character is blind or has mechanical eyes. Anyway, how about the arm thing? I suppose that isn't any easier then?