Maybe a better picture. I can only guess and my guesses are, aiptasia = evil monster
A patch of algae. Could take over all of your rocks.
I can't really say without a better photo of the object in question.
The second pic is much better. Not sure what it could be, but that looks like pretty good live rock. Did you order the rock from somewhere? Sometimes knowing the origin of the rock helps to get ids
Hmm…I’m not too sure, almost has a tube worm (feather duster or similar) look but knowing that it’s from the Florida keys should help others get a better Id for you