Suggestions by @christopher00h

Joe Dante

as Producer in Stand By Me (2006)

Score: +1

Shaggy

as Bufo in Epic (2003)

Score: +1

David Kelly

as General in Wizards (1987)

Score: +2

Whitney Houston

as Where are you Christmas in Dr. Seuss' How the Grinch Stole Christmas (1990)

Score: +1

John Williams

as Composer in Dr. Seuss' How the Grinch Stole Christmas (1990)

Score: +1

John Powell

as Composer in The Polar Express (2014)

Score: +1

Johnny Gill

as Love Survives in All Dogs Go To Heaven (1999)

Score: +2

Vanessa Williams

as Love Survives in All Dogs Go To Heaven (1999)

Score: +2

Kathleen Turner

as Mrs. Thistlewhite in The Year Without a Santa Claus (1994)

Score: +2

Charles Grodin

as Mr. Thistlewhite in The Year Without a Santa Claus (1994)

Score: +2

Richard Hunt

as Weehawk in Wizards (1987)

Score: +1

Frank Oz

as Jingle Bells in The Year Without a Santa Claus (1994)

Score: +2

Phillip Seymour Hoffman

as Mayor of Southtown in The Year Without a Santa Claus (1994)

Score: +2

James Stewart

as Mortimer Duke in Trading Places (1973)

Score: +1

Laurence Olivier

as Randolph Duke in Trading Places (1973)

Score: +1

John Gielgud

as Coleman in Trading Places (1973)

Score: +1

Sigourney Weaver

as Ophelia in Trading Places (1973)

Score: +1

Danny Elfman

as Composer in The Nutcracker and the Four Realms (2008)

Score: +1