Want to ID some critters

[kable8]

Hi all,
Just after some help ID’ing some critters.
first off the guide that’s at the top of F2F hitchhiker page is fantastic, one of the best critter info pages I have seen.
my issue is because I’m still new to this hobby I’m not sure what critters look like when there in the early stages.
please look at the images attached and let me know what you think they are, I have made some guesses but would like some second opinions

 

[Afkomjorgen]

I think the top one are spinoid worms and not harmful. Their population fluctuates with available food. If annoying you can scrape them off. Not sure what the second one is.

 

[EeyoreIsMySpiritAnimal]

First pic - Spirobid worms (spionids are something different)
Second pic - possibly a feather duster
Third pic - possibly a vermetid snail in the crevasse near the top of the rock, definitely a feather duster lower down.

@WheatToast , @ISpeakForTheSeas , what do you think of pic #2?

 

[ISpeakForTheSeas]

First pic - Spirobid worms (spionids are something different)
Second pic - possibly a feather duster
Third pic - possibly a vermetid snail in the crevasse near the top of the rock, definitely a feather duster lower down.

@WheatToast , @ISpeakForTheSeas , what do you think of pic #2?

Agreed with everything you've said here:
1 ) Spirorbids (harmless filter feeders).
2 ) Not entirely sure, but possibly a feather duster (harmless filter feeder) or a medusa worm (mostly harmless) of some variety. I know I've seen something that looks just like this before, but I can't remember what or where at the moment. That said, assuming it's stationary/has a hard tube, I'd lean toward feather duster.
3 ) Probably a vermetid up top and definitely a feather duster below.

 

[freepizza80]

Healthy tank brings healthy critters

 

[Andreas' Reef]

Spirorbid worms, vermetid snails, feather dusters (FREE )