Like others have said 3 clowns will become a problem probably fairly soon.
That being said I had a 22 gallon long and had 2 clowns, 2 cardinals, a tailspot blenny, and a watchman goby with a pistol shrimp. I actually kept my tank too clean and got dinos. Not sure why people are telling you no more than 5 fish. With the right research and upkeep it is doable.
If I was you I would consider re-homing the flame hawk as well. They could become aggressive if you ever wanted to get another bottom dwelling fish that stays smaller.
Overall, I would slow things down here, drop 1 clown from the tank and let things settle in for a while. Then you could look at what else you might want to add. You also need to start testing nitrate and phosphate with a reliable tester so you know what your tank will handle.
