I think before you get rid of anyone, you need to decide what your goals are. Are you planning to breed them? If so what rooster has the qualities your looking for?
Your lavender orp (and the cemani too) may be staying in line because the bcm is in charge.
All roosters will wear some hens feathers away, no matter how many hens you have. They always have favorites.
If you give one up, the pecking order will have to be reestablished. The two remaining roosters may or may not fight.
How old are your roosters?