Suggestions by @matthewfirth

Little Mix

as The Muses in Hercules

+10-6Score: +4

George Lucas

as Director in Star Wars: The Force Unleashed

+2-2Score: 0

Laurence Olivier

as Lord Arthur Holmwood in Dracula (1981)

+4-0Score: +4

Dawn French

as The two old Women in Coraline

+4-1Score: +3

Orson Welles

as Director in Citizen Kane (1951)

+1-1Score: 0

John Williams

as Composer in Captain America: The Winter Soldier (1984)

+2-0Score: +2