bad bug?

Anyone know what these tiny bug/shrimp looking things are? They are all over this rock and under the coral. Are they good for the tank or are they about to kill everything in sight? Thank you!

What up guys first post here bought this Goni a week ago noticed a small mass I thought to be a baby rock flower nem at the time it was only about a half a mm very hard to see but now it’s gotta a bit larger probably almost 3 -5 mm it’s stationary and doesn’t effect the coral this pic was at...

I am wanting positive identification on several different creatures currently in my tank… mostly because I want to know what they are and where they are endemic to. I am building about as close to a Hawaiian Ridgeline/ central indo-pacific ecosystem with all sorts of life that’s habitat/ or has...