I feed frozen: green lifeline, mysis shrimp, daphnia, krill, and cyclopeze. With the tang I would also get some died seaweed or nori and put it in a clip 2-3 x a week if not daily.
The puffer should take the krill and mysis. My concern is the dragonette. How big is your sytsem and how long has it been up? Basically mandarins mostly eat pods
that only exist is a large enough established tank. Otherwise it is basically starving and should probably go back to the LFS
If your system is newer I have seen mine eat the cyclopeze and daphnia, but that is an exception to the rule and will not sustain them forever.
I would discontinue the frozen brine shrimp. It has no nutritrional value and is mearly a treat. It is similar to feeding them twinkies. The mysis would be much better.
Oh, I also use some marine flake and pellets in an electric feeder as I am not always home.