Suggestions by @highmore

Steve Coogan

as Constable Bertram in Carnival Magic

Score: +1

Rob Brydon

as Constable Rogers in Carnival Magic

Score: +1

Jonathan Ross

as Johnny Ricket in Carnival Magic

Score: +1

Jimmy Carr

as Taylor the Ticketmaster in Carnival Magic

Score: +1

Jo Brand

as Gloria the Bearded Lady in Carnival Magic

Score: +1

Mac McDonald

as Bimbo the Clown in Carnival Magic

Score: +1

Rowan Atkinson

as Pierre the Mime in Carnival Magic

Score: +2

Bill Bailey

as Raymond the Acrobat in Carnival Magic

Score: +1

Tamsin Greig

as Emma the Juggler in Carnival Magic

Score: +1

Dwayne Johnson

as Gordie the Lion Tamer in Carnival Magic

Score: +1

Eddie Izzard

as Orville the Ringleader in Carnival Magic

Score: +2

Jonathan Lipnicki

as Danny Horn in Carnival Magic

Score: +1

John Lithgow

as Marvin Horn in Carnival Magic

Score: +1

Josh Peck

as Luke Sweeney in Carnival Magic

Score: +1

Mischa Barton

as Jennifer Sweeney in Carnival Magic

Score: +1

Molly Shannon

as Matilda Sweeney in Carnival Magic

Score: +2

Martin Short

as Patrick Sweeney in Carnival Magic

Score: +1

Kirsten Dunst

as Kendra Wachowicz in Carnival Magic

Score: +1

Jodie Foster

as Maple Wachowicz in Carnival Magic

Score: +1

Robin Williams

as Burt Wachowicz in Carnival Magic

Score: +2