Suggestions by @jacobking1

Rex Harrison

as Elrond in Lord of the Rings Trilogy - Old Hollywood (1950s)

Score: +2

Stephen Boyd

as Merry Brandybuck in Lord of the Rings Trilogy - Old Hollywood (1950s)

Score: +1

Anthony Perkins

as Peregrin Took in Lord of the Rings Trilogy - Old Hollywood (1950s)

Score: +1

Ray Fearon

as Vulkan in Warhammer 40k: The Horus Heresy (Amazon)

Score: +1

John Gielgud

as Gandalf in Lord of the Rings Trilogy - Old Hollywood (1950s)

Score: +2

Thomas Mitchell

as Bilbo Baggins in Lord of the Rings Trilogy - Old Hollywood (1950s)

Score: +1

Roddy McDowall

as Samwise Gamgee in Lord of the Rings Trilogy - Old Hollywood (1950s)

Score: +2

Dean Stockwell

as Frodo Baggins in Lord of the Rings Trilogy - Old Hollywood (1950s)

Score: +1

Kirk Douglas

as Boromir in Lord of the Rings Trilogy - Old Hollywood (1950s)

Score: +1

Richard Burton

as Sirius Black in Harry Potter (1950s)

Score: +2

John Gielgud

as Professor Albus Dumbledore in Harry Potter (1950s)

Score: +1

Michael Hordern

as Rubeus Hagrid in Harry Potter (1950s)

Score: +1

Christopher Lee

as Severus Snape in Harry Potter (1950s)

Score: +2

Laurence Olivier

as Lord Voldemort in Harry Potter (1950s)

Score: +2

Dana Wynter

as Arwen in Lord of the Rings Trilogy - Old Hollywood (1950s)

Score: +3

Gregory Peck

as Aragorn in Lord of the Rings Trilogy - Old Hollywood (1950s)

Score: +2

Daniel Craig

as Benoit Blanc in Wake up Dead Man - A Knives Out Mystery

Score: +1

Rian Johnson

as Director in Wake up Dead Man - A Knives Out Mystery

Score: +1

Mads Mikkelsen

as Actors in Actors and Actresses that should join the Alien Franchise

Score: +1

Clint Walker

as Zeus in Hercules as a 1950s Epic

Score: +2