Although someday I’ll try to write something more thorough, here goes on a short summary of my observations/experiences for dwarf angels, butterflies and reefs that relate to your question. I have a 520 gallon 10 foot tank. I have softies, some hardy SPS, and LPS… nothing fancy. The tank is well fed. I have the following dwarf angels: nox, flame, rusty, coral beauty, yellow, flame back, and eibli. I also have the following butterflies: double saddle, Indian vagabond, 2 X pearl scale, 2 X longnose, 2 X lemon, Pakistani, latticed, atlantic reef, Klein’s, peppered, spotband, 4 spot. I cannot keep monti nor most frogspawn or hammers, though do have one frogspawn that they have always left alone… go figure. Theses corals were decimated by the double saddle, latticed, and spotband… though mostly the double saddle and only recently. I’ve tried CBs, but they seem too shy to adapt to the other butterflies’ feeding cadence…. I never witnessed the dwarf angels touching coral. The butterflies all get along very well. Probably the least conspecific aggressive fish I’ve ever had other than shrimp gobies and my three purple tilefish. The dwarf angel aggression is limited to the coral beauty occasionally chasing the rusty, though it took a long time for the nox to be accepted and the eibli will not allow me to add a halfblack.
Hope this helps…