Misc: how many instruments accompany someone singing a cappella?

Questions

B Movies: Say his name 3 times....?

B Movies: Song: "and I said, what about _ _ _, & you said I think I remember the film?

B Movies: Tom Hanks may want to forget he did this 1984 T&A comedy?

Back To The Future: If future events are altered, photos and writing from the future become _?

Back To The Future: In BTTF 3 Doc Brown finds true love in this woman (full name)?