Technically, Dorvilleid worms are bristleworms (and so are bobbit worms, and tons of others too) - bristleworm is technically just a term to refer to polychaete worms (regular bristleworms, fireworms, eunicids, dorvilleids, etc.). Anyway, I agree that the worm in question looks like a Dorvilleid worm (and it’s most likely harmless like most bristleworms).
I also agree that the rest are hard to make out, but I don’t see anything that looks like it could be something particularly bad.