I agree with cassharper. At the least maybe just get 2 more since they will establish a pecking order and this will distribute the amount of aggression any one discus will get. (maybe from the same place so they can sort of quarantine together as they are from the same source)
As for your choice of discus, I'd say they are very nice! Your blue turquoise looks outstanding. I also think it's a good thing you didn't start with a bunch of juveniles, which take alot more work to prevent them from stunting.