3 festivum could work but if tow pair up the third might get harrased too much. That's why I like 5 any argession is spread around and no ne fish has to take the brunt. A pair of wild peruvian scalar whould ok with the discus but just watch out if the Angle fish start to bully the discus or prevent them from eating. A mated pair of angelfish will have the discus stressed and huddled into a corner. The dynamic has to be balanced and watched carfully, non species specific discus tanks can be tough to get right if they are not the dominant fish in the tank or have too much compatition for food they will fade.