Suggestions by @lahkyk

Sophia Bryant

as Mary Macdonald in Hogwarts

Felix Mallard

as Teen Cygnus in Hogwarts

Thomas Weatherall

as James Potter in Hogwarts

Golshifteh Farahani

as Emmeline Vance in All the Young Dudes

Steven Yeun

as Frank Longbottom in All the Young Dudes

Aneurin Bernard

as Severus Snape in All the Young Dudes

Dev Patel

as James Potter in All The Young Dudes

Kathryn Newton

as Pandora Lovegood in All The Young Dudes

Karen Gillan

as Lily Evans in All The Young Dudes

Vanessa Kirby

as Petunia Dursley in All The Young Dudes

Richard Madden

as Rodolphus Lestrange in All The Young Dudes

George MacKay

as Grant Chapman in All The Young Dudes

Tom Hardy

as Alastor Moody in All The Young Dudes

Arthur Darvill

as Arthur Weasley in All The Young Dudes

William Moseley

as Danny McKinnon in All The Young Dudes

Caitríona Balfe

as Minerva McGonagall in All The Young Dudes

Ryan Destiny

as Desdemona Lewis in All The Young Dudes

Algee Smith

as Roman Rotherhide in All The Young Dudes

Colin Firth

as Orion Black in All The Young Dudes

LaKeith Stanfield

as Castor in All The Young Dudes