You say Charles Laughton is buried at Forest Lawn in Glendale when he is buried in their Hollywood Hills Memorial Park. I'm a property owner there so I know these things ;)
Oooh that’s an interesting question and I am not sure. I believe all three are in that and that serves as an enclosed mausoleum but I may be wrong. I’m just guessing. Please update me if you know the answer as that is a great question.