I have to dissagree, if you introduce the pygmies so they can get established, what I do is put them in a small pals clear container for a week before I let them out into the main tank, IMO you will be fine. I have a pr of cherubs, a trio of potters, a pr of fishers and a single flame in my 75 gal reef, and the only trouble I have ever had was in the first few days of adding a new fish.
I don't know how easy it will be, and cherubs are much more agressive then the flames, but the flames are established and probably bigger, both of which will help
good luck no matter what your decision is.