Then everyone is crazy. You have WAY too many fish in your tank, regardless of being syngnathiformes, and you will experience problems. Its not a matter of if but when. You should have somewhere between 4 - 10 gallons of water per inch of fish aquarium. The variation is due to territoriality, body size, and waist production. Seahorses are going to lean somewhere closer to the high end because they are poop machines.
With your setup, I'd say you need a minimum of a 30 gallon, and that is even very crowded. Take pledosophy's advice and get a 55 now, so you have time to get it established BEFORE there are problems. 55 gallon tanks are cheap at walmart, so it isn't even a huge expense.
As for the bristle worms, why do you want to get rid of them? They are beneficial. If you have too many, then the tank is being overfed. Which sounds pretty likely considering the tank size and the number of animals.
Also, the CBS has GOT to go. Its another not if but when scenerio.