height

The problem with answering your question is that the heights of Lugosi and in particular Chaney are uncertain. Bela is listed here at IMDB as 6' 1-1/2". I can accept that as in the films he co-stars in with Karloff he looks to be a couple of inches taller than Boris (who I've read was 5'11"). The heights I've read for Chaney vary from 6' to 6'4". I'll go with 6'2" for Lon. If Bela really was 6' 1-1/2" tall he should be about 6'6" in the monster costume. The elevated boots look to be built up 4" and the headpiece would probably add another inch. The thing to bear in mind is that the movie studios publicity departments tended to add somewhat to actor's heights. Bela may have been 6' even, Boris 5'10" and Lon 6'1" for all we know.

The Monster was shorter in this movie because it was stuck in frozen ice for many years. When a body is frozen in ice, parts of the body start to shrink. Sort of like when you have a swelling on your body, you apply an icepack to subdue the swelling. So in this case, the Monster was a few feet shorter due to the ice melting some of his height away