I'm not sure on these but here's some guesses.
Marty: ESTp or ESFp
Biff: ESTp
Lorraine McFly: ESFj
George McFly: IXTj
Doc' Brown: ENTp
Clara, the schoolteacher and Doc' Brown's girlfriend in BTTF III ??? I've been wondering about her, do you think she's his dual?
What are your takes?
And if you can think of anybody else noteworthy in those movies, type away...