10 suggestions

Miles Teller
as Severus Snape in First Wizarding War

Johnny Flynn
as Arthur Weasley in First Wizarding War

Haley Bennett
as Molly Prewett Weasley in First Wizarding War

Kit Harington
as Severus Snape in First Wizarding War

Samantha Isler
as Lily Evans in First Wizarding War

Joe Cole
as Peter Pettigrew in First Wizarding War

Max Minghella
as Remus Lupin in First Wizarding War
Xavier Dolan
as Sirius Black in First Wizarding War

Jack Lowden
as James Potter in First Wizarding War

Finn Wolfhard
as Ezra Bridger in Star Wars Rebels