Suggestions by @nathanialprice

Sophie Rundle

as Marlene McKinnon in The Marauders

Score: -34

Fionn Whitehead

as Severus Snape in The Marauders

Score: -18

Dean-Charles Chapman

as Peter Pettigrew in The Marauders

Score: -16

Thomas Brodie-Sangster

as Evan Rosier in Marauders

Score: +4

Keeley Hawes

as Minerva McGonagall in Marauders

Score: +1

Charlie Heaton

as Barty Crouch, Jr. in Marauders

Score: +2

Kaya Scodelario

as Andromeda Black in Marauders

Score: -1

Sophie Rundle

as Marlene Mckinnon in Marauders

Score: -4

Ellie Bamber

as Narcissa Malfoy in Marauders

Score: -2

Bill Skarsgård

as Voldemort in Marauders

Score: 0

Dean-Charles Chapman

as Peter Pettigrew in Marauders

Score: -1

Fionn Whitehead

as Severus Snape in Marauders

Score: -4

George MacKay

as Remus Lupin in Marauders

Score: -14

Dev Patel

as James Potter in Marauders

Score: -7

Keeley Hawes

as Minerva McGonagall in the Marauders

Score: +2

Dean-Charles Chapman

as Peter Pettigrew in the Marauders

Score: +3

Fionn Whitehead

as Severus Snape in the Marauders

Score: +1

Sophie Rundle

as Marlene McKinnon in the Marauders

Score: +4

Dev Patel

as James Potter in the Marauders

Score: 0