Casting & Costume
King Duncan would be played by Robin Williams. Williams is an older man, and he has a friendly and charming look to him. He would be perfect for Duncan.
Donalbain would be played by Jerry Trainer. Trainer also looks similar to Malcolm and Duncan so they would most definitely look like a family.
Malcolm would be played by Hamish Linklater. Linklater has that same friendly charming look as Duncan meaning they would believably be able to be father and son. Linklater looks like the good guy that Malcolm is, but could easily throw on a evil sort of act during the part of the play where he tricks Macduff into thinking he is a bad person.
All three of these men will wear smiilar style suits