Good call on the neon goby
Good call on the neon goby
The major problems I see are that the Dragon wrasse will almost definitely eat the urchins, and the jackknife not only grows big but is somewhat difficult to feed and appears to need high flow.
Curious wormfish are pretty easy prey for damn near everything, even some shrimp and crabs otherwise thought as reef-safe. My only qualm with fang blennies is that they are venomous and can injure people. They are however largely immune to predation from fishes that inhale prey (such as scorpionfish).
You also have several fish that can be difficult to feed, including the dragon goby and scooter "blenny".