Of the list you mentioned, vermetid snails, colonial hydroids, and gorilla crabs would be something to consider acting on if you corals in your tank.
Colonial hydroids are a pain to eliminate. You can do it by hand or use kalk paste. I struggled controlling these, so if it’s isolated, I suggest removing the rock entirely, drying it out to kill everything, then re-cure it.
Vermetid snails can be physically crushed up, or there are natural options like some wrasses or bumblebee snails.
Are you sure the crabs are Gorilla crabs? Typically don’t see them come in as a hitchhiker on coral frags which is the only way I could assume you got them if you didn’t use live rock. You can try to catch them with a trap or remove the rock they are in and use tweezers. Some will just try to spear them in the hole they are hiding in
Bristle worms are good cleanup, but their population can get out of control if there are excessive foods in the tank.
Pineapple sponges are harmless filter feeders.
