The johanni species is typically more aggressive, though I would expect an adult male cyaneorhabdos to be more aggressive than a johanni female.
I would remove the johanni females. I would also remove the Green Terror, it is simply going to get too big for this tank, and will be disruptive. Without removing it, I wouldn't add any other fish. You could add in some Ps. acei, and perhaps a Cynotilapia afra type.
I would remove the johanni females. I would also remove the Green Terror, it is simply going to get too big for this tank, and will be disruptive. Without removing it, I wouldn't add any other fish. You could add in some Ps. acei, and perhaps a Cynotilapia afra type.