I have a fully grown yellow tang in the tank and added two female Watanabai. It was pretty hectic at first, the tang kept trying to spike them with its tail and chased them around the tank. Literally after a day, the tang laid off and let them be if it had jumped them both into its gang or something. The larger female chases the little female Wananabei all the time trying to show dominance I guess. I've had them for a month now but no sign of any sex change yet.
They are both very lively and bring a lot of color into my tank. Not shy at all, they look like they schooled up with my chromis in a way. They both eat like a horse, algae sheets, pellet, flakes, you name it.
I also notice that one of my Wantanabei picking at my sps at one point, didn't really do any damage but they do get curious sometimes.