Well, I'd go with less than you have now...
The angel should be okay, size-wise, But, they can be territorial towards similar colored or shaped fish.
The clown will get up to 5 inches, and may be a bit cramped in a 30. Should be okay, but like the angel, will be territorial and aggressive.
The Watchman is fine--It will stake out a spot, and defend it, but typically leave other fish alone.
The scooter may be fine--a lot will depend on how much quality live rock you have and if it will take prepared foods. Like other dragonets, they can refuse all but live food and a 30 with 30 pounds of rock own't be productive enough to keep one alive for long.
The hogfish--I'd take it back. They get up to 8 inches, and that's a lot for a 30 gallon tank. They tend to be aggressive fish, and will eat the same micro-crustaceans preferred by the scooter.
I'm also not a fan of the horse shoe crabs. They're cool, but very tough to keep well fed and healthy, and are prone to being tipped over and stranded in smaller tanks or those with lots of rock---they really need large, open sandy beds to thrive.
Just me, but I'd get rid of the hogfish, the horseshoe crab, and probably the scooter. You could add more in the way of some shrimp or peaceful crabs, but I would not add anymore fish, even if you removed the ones I listed.