As to the above stocking, I think you'd be okay if you replaced the filefish with something itty bitty.
My tank (same size) has a 1 1/3" blue damsel, a 3" waspfish, and a 1 1/4" shrimpgoby, plus the 2-3" pistol shrimp. I would feel comfortable adding 1-3 more fish, provided they stayed 2" or under, but my waspy ate the Hector's goby I tried to add, so I'm just leaving it alone for now. I plan to add one nice molly and another tiger pistol shrimp, then I'll just leave it at that.
Just my 2cents... Stocking depends on how much live rock you have, what the personalities involved are, what non-fish stock you have, and how often you do water changes, plus others. It can be really complicated.