They work great together water needs as far as being clean are simular the tall body of discus "usually" will stop a peacock from haven Lunch LOL!! They can be mean just depends on the fish ya know ...I have kept Uaru /discus /severum /even small cats like Rafael and still do with my p's under two foot!!!
I have yet seen pbass with discus before nor would I attempt to do such thing. Due to the fact that (when feeding) bass don't care who is in the way of the food and the bass will rush it and could cause stress on the discus.