These are palythoas...they are hardy and with improved conditions will be fine. These green ones are commonly called Button Polyps.
It looks like a finger leather coral. With improved conditions it should make a recovery. If the tissue in the center is still dying, you might consider cutting the "fingers" off from around it and put them in some rubble or small pieces of rock to reattach.
The green one is a green nepthia. The brown one on the top right looks to be a cabbage leather.
I can't really tell on this one. Perhaps if you can get a clearer photo that is closer.
In general, I would say everything that is still alive is pretty hardy (obviously). And if you can improve their water quality and provide ample flow and lighting they should recover.