Hi Colin - maybe this reply is too late but I have a Flameback in a 15G for several months now and I love it. I have it with a 6 line (who has been a model citizen) and a yellow coris wrasse and they are fine. I also had a fairy wrasse and the angel did pester that and so I removed it.
I looked up this thread to see if I could find anything about pygmys eating clove polyps as one got eaten overnight but I think it's my emerald crab (my small zoas have never been touched). I heard these are reef safe (and I looked it up before I purchased it).
I did purchase it because it is such a beautiful fish - I had seen them online but in person they are stunning. I am soon moving the angel into my new RSR250 - the emerald probably won't be going in with it