I googled transforming octopus mask and It came up as Tlinget from the Alaskan culture.So on that you are correct.I'll try and figure out the artist.Maybe John Nardone.
Another big (John) name in Pacific Northwest transformation masks is John Marston, but I couldn't find his signature. I also felt like with the makers mark maybe it started with a J, since it looks like two crossed J's, although if the last name begins with a J it doesn't look like the one in John.