I would skip the Dragonet unless you plan on supplementing their feedings or add pods on a regular basis--they are best suited for well-establised, and large, reef tanks or a slow paced seahorse tank.
I see varying opinions but I think the Cherub would work. Mine used the complete length of the 125 gallon but after seeing them while diving, I doubt he was impressed with my 6' tank... it comes down to what you think is morally right and I won't judge either way, being that we all take fish from the ocean and put them into something much smaller than they prefer. Is any Emperor Angel truly happy in a 400 gallon aquarium?
I do like fishyfish69's idea of a Tailspot to get a similar type of fish but one that'll stay smaller to decrease your bio-load. However, if you just really want the Bi-color get it. I had one in my 75 that did show aggression towards my 1.5" Jewel Damsel but had no issues with my Orchid Dottyback--keep in mind that was a much larger tank.
Dottybacks are typically pretty aggressive but I would say that the captive bred Orchids are about as chill as they come. Also, the pygmy angels don't take any crap and can show aggression themselves--my 1.5" one liked to pick on my 3" yellow watchman goby.
If you end up with the Cherub, Orchid and either blenny, I would add them at the same time. To be able to keep your levels in check by adding that many in a small tank, I would stock it with 3-4 Damsels and swap them out when the time comes.
Good luck
Mike