How big is the tank?
Even with 3 females and 1 male the male could end up dead or badly injured, females dead from each other or from the male.
The stress alone can be caused to all the fish that can inhibit the immune response due to poor stocking choice..... even with lots of hiding places unless they are in at least 55g or larger with 50-75% plants both rooted and floating to kill the line of site.
It is good that you have a back up plan in place
Also, even with 3 females..... they will spawn- when the female is ready she will go to him- the females eggs will ripen due to the hormones emitted by the male- the male will be drawn to the females as she becomes ready from the hormones emitted by her.....after the females eggs ripen over and over and she either spawns, absorbs or drops the eggs, it will shorten her life span...thats just part of the cycle.........