Hello, I breed my cockatiels and doves together and have been doing this for years. I have never had a bit of trouble with having them all together like this. I have also bred my finches in with my cockatiels as well.
I was just looking at the size of the cage..... I is just right for one pair of breeding cockatiels. I did not catch the size of cage and had assumed that you had a large aviary. NO i would not put any more then just one pair of cockatiels in that size cage.