CBB update:
It's been a few days, and it's still eating frozen mysis; furthermore, I've also noticed it picking at the rocks.
In better news, I also noticed it swimming about more freely, with the PT pretty much ignoring the CBB.
In not so good news, the PT won't go near the trap; it's as if it knows I'm trying to catch it. I tried not feeding for 24-36hrs, then placing frozen food within the trap. No luck-the wrasses would venture in, start picking at the food, with the food ultimately drifting out of the trap. That is when the tang comes out and gets it share. Otherwise, it just stays underneath the shelves, or swims back and forth along the back.