The general rule is that bickering is to be expected, but once a fight progresses to one bird pinning other down they must be separated permanently. So, no, it would not be safe to ever put the birds all back together.
It is quite possible that the cause of Apple's aggression was the presence of Mozie and that he and Kiwi would be fine without her in the mix, but I wouldn't risk it. The potential for disaster is too high.
I hope you can find other cages you love.