If Marty McFly were genderbent, his genderbent name would be Mary McFly
If Doc Brown were genderbent, his genderbent name would be Doc Emma Brown
If Biff Tannen were genderbent, his genderbent name would be Bianca Tannen
That's all i got. I can't think of any others. I can't think of any other gender bent names for the other characters. It's so tough trying to come up with genderbent names that sound similar to their actual names. If あなた guys could come up with some genderbent names for the ones i forgot, that'd be great ;).