ID Please?

My guess

First picture looks like a type of bristle worm. Some people like them and some get rid of them. They are good cleaners and clean up extra food and poop and dead things in your tank. They come on your live rock.

The other #3 is a feather duster if it is white it is probably dead but look around you probably have a lot more.

#2 my guess is a polyp of some kind. They open when they feel comfy and mine only open under some kinda light.

#1 I don't know but it is pretty!

 

As far as I can tell, feather dusters are white when they are really small and still developing (as it appears in the picture). Feint darker bands develop after that. Mine are almost solid white except for the slightly larger ones, forming the aforementioned bands, and they all tuck away when the light changes, even if it's just a slight shadow, like if I am looking around in my tank and move over it.

 

number 1 looks like something i once had when i first started in the hobby. Mine was some kind of algae, flaked apart when touched and never seen it again.