Suggestions by @bobmuse

Iain Armitage

as Hans Katzenjammer in The Captain and the Kids

Score: -1

Harrison Ford

as Gen. Halftrack in Beetle Bailey

Score: -1

Jonathan Lipnicki

as Beetle Bailey in Beetle Bailey

Score: +2

Yakov Smirnoff

as The Inspector in The Captain and the Kids

Score: +1

Arnold Schwarzenegger

as The Captain in The Captain and the Kids

Score: +1

Rosie O'Donnell

as Mrs. Katzenjammer in The Captain and the Kids

Score: +1

Danny Elfman

as Composer in The Grim Adventures of Billy and Mandy

Score: +1

Jack Black

as Sgt. Oliver Snorkel in Beetle Bailey

Score: +2

Christopher Eccleston

as Saw Boss in Jayce and the Wheeled Warriors

Score: +2

Will Smith

as Herc Stomsailor in Jayce and the Wheeled Warriors

Score: +1

Violet Tinnirello

as Flora in Jayce and the Wheeled Warriors

Score: +2

Sylvester McCoy

as Gillian in Jayce and the Wheeled Warriors

Score: +1

Peter Davison

as Audric in Jayce and the Wheeled Warriors

Score: +1

Tom Holland

as Jayce in Jayce and the Wheeled Warriors

Score: +1