I had a PPE frag get attacked by an acan and it closed up for over a month, shrivled up and grew algea over it, 2 weeks ago I pulled it out wiped off all the algea, piled superglue gel all over it except the mouth and WALA... its now fully open and starting to spread, as soon as I see a new polyp starting, it will be going to its new owner.
Moral of my story... Zoa's are INCREDABLY resiliant, you need to figure out why those polyps are closed. Take a flash light to them at night and stare at them for a min or 2, give the colony a fresh water dip or a saltwater one with a little H2O2 in it to give them a boost.