Is there anyone who might know what the film title is that VP played as a twin double? I believe the characters names were nicholas and edward? Thanks for any input.

Well, I think you might be remembering "The Oblong Box"(1969)in which Vincent has a brother named Edward who is horribly mutilated and kept under lock and key at the family estate. Vincent's character is named Julian, however, and not Nicholas. Apparently in an early version of the script, however, Vincent was cast to play both of these characters. In the final film, he did not. Regardless, it's still a lousy film. Look elsewhere for quality VP.

Maybe Kate is thinking of PIT AND THE PENDULUM. VP played Nicholas, who goes mad and thinks he is his father Sebastian. So you could call this a double role.