Suggestions by @harrypotterfan7

Christian Bale

as Sir Nicholas De Mimsy-Porpington in Harry Potter

Colin Hoult

as Edward "Ted" Tonks in Harry Potter

Rhys Matthew Bond

as Regulus Arcturus Black in Harry Potter

Asa Butterfield

as Regulus Arcturus Black in Harry Potter

Harry Lloyd

as Regulus Arcturus Black in Harry Potter

Leo Suter

as William Weasley in Harry Potter

Fionn Whitehead

as Charles Weasley in Harry Potter

Alex Lawther

as Charles Weasley in Harry Potter

Ralph Fiennes

as Voldemort (present time in the book) in Harry Potter

Kelly Macdonald

as Helena Ravenclaw in Harry Potter

Simon Fisher-Becker

as Fat Friar (Hufflepuff ghost) in Harry Potter

An Unknown Child Actor

as Dudley Dursley in Harry Potter

Tom Hollander

as Rubeus Hagrid in Harry Potter

Michelle Fairley

as Professor Minerva McGonagall in Harry Potter

Alan Cumming

as Xenophilius Lovegood in Harry Potter

Mackenzie Crook

as Argus Filch in Harry Potter

George MacKay

as Morfin Gaunt in Harry Potter

Ben Hardy

as Morfin Gaunt in Harry Potter

Freddie Highmore

as Morfin Gaunt in Harry Potter

Will Poulter

as Morfin Gaunt in Harry Potter