I think you may have misinterpreted what I said... I never actually said that I didn't think ReDead masks weren't made of coffin wood (I actually think that makes sense), I was just pointing out that the lines of the two characters do not actually tell us that... certain assumptions need to be...
Would you want to keep wearing a mask that had been made from an old coffin? Whether or not it had once been worn by a ReDead is irrelevant to Dampe's line... either way it's creepy and not something you'd really want on your face.
That logic makes no sense whatsoever... why wear a mask with...
The lakeside scientist's line is a little misleading... it doesn't actually say that ReDead masks are made out of coffin wood, only that the Spooky Mask is.
It's worth noting that the WW ReDead don't wear masks, and the ReDead in TFH appear to have masks made of some other material (I'd guess...
I think the clay thing could have some truth to it, especially considering their appearance in Tri Force Heroes... the myth about life being created from clay is present in many cultures around the world, so I think that's what ReDeads are... either failed or incomplete attempts to create life...