Pretty sure all three are palythoa, the infamous Texas Trash Palys. These things spread like the plague and as you can probably tell are notoriously difficult to kill (hence why they survived on that rock and have popped up again).
I had the same thing happen in my first tank and they spread everywhere. I wish I had gotten rid of them when there were only a few of them. You can certainly keep them, but as I said they spread fast and don't look particularly good either. Not to mention they contain palytoxin.
Now that there are only three of them you can just remove them with tweezers during a water change, being sure to get them in the syphon as you remove them from the rockwork. It's also a good idea to run fresh carbon afterwards as you don't want any palytoxin in the water column if you can help it.