As for pairing Emperors, you might want to search up John Coppolino (copps on RC) and see what he did.
John is a MASTER reefmaster!
It's MY OPINION that if you populate your reef aquarium with lots of diverse microfauna you will GREATLY reduce the amount of food required by the fish you've suggested.
One of the best ways of introducing that microfauna is with the use of some "really live" liverock.
I added my Emperor with some corals already in the aquarium- the NEW CANVAS thread shows exactly when.
If you maintain the aquarium properly, damage by your Imp can be minimized (note my choice of wording. Every fish is different!)
Too much sterility and too many frag tanks nowadays. That's my opinion.
Let me know if you find copps incredible build.... and check out my buddy Bradley Syphus...he's got one helluva reef aquarium!
Good luck with your build!