Blockheads do not have noses. The default skull brick has nostrils. The skull brick looks weird because it's not accurate and it doesn't have to be.
Does the coffin have opening/closing events like the doors?
Support_LegacyDoors add-on - This is an optional replacement for JVS_Content. It makes JVS doors work and animate but uses far fewer events, and it doesn't cripple normal brick loading time like JVS does. It also puts all JVS doors under the Special->legacy doors tab. To use it just enable Support_LegacyDoors under a custom game.
I don't know why but the skull doesn't look like it belongs to a blockhead, Maybe because of the jaws