Andy, that's a gorgeous mix of fish there! Very similar to mine. Your dussumieri is nice, displaying the lighter colors there that mine typically do not display. What are the sizes on your fish?
For my fish, other than the "big guns" that are pictured, there's a pair of mandarins (female is too small to begin spawning yet but she's the first to survive introduction to the big male), a single firefish, a mystery wrasse, a solarensis wrasse, a lycopod that I see when I shine a flashlight into the crevices of the tank, a single gold headed sleeper goby (lost the female in the toilet debacle along with my school of anthias and one of the yellow tangs), and a 3 stripe damsel. I think that's all, although fish do surprise me periodically by popping up (shrimp, for example, are in there, but I see them about once every 2 months due to the rock).
I've got tons of rock and there's tons of spaces between them and lots of arches but also lots of open space for swimming. I feed heavily, about a handful per day, and also clip 2 sheets of nori in there every day or so. I rarely feed much else because my pod population is booming and every time you look into a crevice you can see the mysis swimming around.
Oops, forgot about my pair of black ocellaris and my pair of orange/pink skunk clowns that are currently going through some rough times and are doing a trial separation

. There's also other fish in various sumps or frag systems connected to this, but none have access to the display.
It is a good idea to look at this from the perspective that I have a lot of experience in the hobby, I take things slowly and I don't take on difficult species without doing thorough research and acclimating for a long time. I would say that out of the risks I took in this system, the biggest risk was introducing the Imperator after having the 2 regals.
The coolest thing is to still see them when I'm not in sight of them - they school as a large group back and forth, but when I'm down there it's all about getting my attention to eat.