Suggestions by @evdog

Sidney Poitier

as Lenny Summers in 1964 Red Dead Redemption

Score: +2

Sharon Tate

as Mary-Beth Gaskill in 1964 Red Dead Redemption

Score: +3

Steve Buscemi

as Seth Briars in Red Dead Redemption.

Score: +4

Robert Downey Jr.

as Josiah Trelawny in Red Dead Redemption.

Score: +43

Winston Duke

as Charles Smith in Red Dead Redemption.

Score: +22

Christian Bale

as John Marston in Red Dead Redemption.

Score: -23

Chadwick Boseman

as Hercule Fontaine in Red Dead Redemption.

Score: +19

Donald Glover

as Lenny Summers in Red Dead Redemption.

Score: +46

Carrie Fisher

as JF_H()NIPQMW{ in The New Order

Score: +4

Frank Morgan

as The Wizard in The Wizard of Oz 2 Back To Oz (1955)

Score: +1

Ian McDiarmid

as Mr. Burns in Live-Action Sipmsons Fancast

Score: +3

Carrie Fisher

as Catwoman in Batman film from 80s

Score: +2

Ian McDiarmid

as Joker in Batman film from 80s

Score: -1

Willem Dafoe

as Joker in Batman film from 80s

Score: +7

Billy Dee Williams

as Lando Calrissian in Star Wars - Episode VII: An Ancient Fear

Score: +2

Alec Guinness

as Obi Wan Kenobi in The Star Wars Sequel Trilogy (Alternate)

Score: +2

Heath Ledger

as Joker in Batman: The Dark Knight

Score: +3