Update, if I can even call it that.

I did a FW dip on the shrooms and a Furan dip on the zoas.

I broke the zoas up. (Not entirely on purpose...) After the dip, I put one back in the original spot and some others far from the mushrooms. The colony that is further away has 12 polyps open, 2 closed. The frag put back in the original spot has 11 open and 18 closed. That's still more open than before. Too soon to blame the mushrooms I guess, but I won't dip again since I don't see any white bumps on the stalks.