Today, I can report that all is well in the aviary, it has taken some thought, but the chicks appear to be thriving and the adults content. The image of three hens in one nest was a concern, there were 11 eggs, which all three birds claimed, inevitably two eggs smashed.
I placed another nest in the cage in the exact place of the disputed nest, putting 4 of the 9 eggs in, moving the original nest with the remaining 5 eggs close by. Happily the two orange females are now sitting on these, they do glare at each other! I have moved the brown canary hen into another cage.