How is the larvae doing?
Having one success, I have nothing to really share since I just followed Chappy's video and didn't have repeatable success after that. I didn't test the water or anything but the parameters should be like how you are trying to keep things alive and flourishing. Just try it and don't over complicate it as you can see in other videos of people there's no much to it other than a food source and stable parameters.
So view his video and try his method, the only exception is to start the tank way sooner than later. The ones who have success are probably the ones selling them to the stores but it looks like someone in the larger distribution have started to breed them. What they sold over 7+ years are monsters compared to what htey sell that I saw at Petco, they looked smaller than adult neos.