yes, easily. the BN's won't bother the cichlids since the male will spend all his time hiding in the cave guarding the eggs, and the rams aren't big enough to have any sort of affect on the plecs. however, the rams might try to eat baby BN's, and the big BN's will probably try to eat the ram eggs. you might have to get a separate tank to actually raise the babies, but breeding itself shouldn't be a problem as long as you have fish that want to breed. if that answers the question.
Its a fine choice. But you would have to divide the tank.The Bn's would spend their time in the dirftwood/cave with the eggs, fanning them. Whilst the rams are out in full force doing thier thang.