So many hitchikers!

[Maebh]

I havent half a clue what these are, but here are some guesses. Thanks to anyone who can help!
Pic #1 Green bubble algae?
Pic #2 Cats purse-red, old shell-green.
Pic #3 Vertimed snails-red, algae-blue, little cave made of sand-green.
Pic #4 Sand cave.
Pic #5 white fuzz- cats purse, shell, and cave.
Pic #6 Veiny leather coral.
Video:
-Fire bristle worm-center rights
0:22,0:24,-Weird pop out guy-beside big white fluff.
0:28,0:40-48-odd amphipod-above big white fluff.
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[JonsNano]

1st photo the green looks like possibly ulva, in the 3rd photo the red circled/squares look like possible hydroids the green circle looks like what ever that pile of is in the bottom of the 5th photo, and the 6th photo looks like sponges and feather dusters and some ulva leading me to think that those possible hydroids might be possible feather dusters lol

 

[JonsNano]

Just watched the video and that little ‘weird pop out guy’ moves very quickly!

 

[ISpeakForTheSeas]

To link the threads here:
https://www.reef2reef.com/threads/bunch-of-stuff-take-two.1034021/#post-12175492