I've finished it now - not completely happy with what I have for 19ac. Once you've got a few answers, not as bad as it looked. Not so many matching answers that you could call a theme - more a devilish Araucaria. Go with 1 dn seems to sum it up.
I knew only one word that would fit the pattern, and it wasn't that. I put the threed letters I had into "Chamber's Word Wizards"; that gave me three possibles, and it was one of those.
If you don't know "C W W" I recommend it.