Budgies and cockatiels aren't a good mix with doves or finches. Budgies especially can be bullies. But you could put Neophema/Grass parakeets such as the Turquoise, Scarlet Chested (they are a bit delicate though) or Bourkes parakeets in there and they would be beautiful and peaceful. They really are beautiful birds that have the sweetest songs and don't act aggressively towards other members in the aviary. If you want to breed them it's best to keep one pair per aviary.