The most difficult thing for pumping the NPS is intelligence.
Laika studied at the academy for 3 years. 120 intelligence did not gain. 114 only.
The rest of the skills grow cheerfully at the academy.
For pumping combat skills and discipline, you can put a guard.
Teachers pump skills well.
I pumped something myself. Mostly teachers. And the teachers pumped the rest. 3 teachers pump 12 people at a time.
But having played 1200 days, I came to the conclusion. The main combat party of 4 people needs to be pumped. The rest is much less important or not at all. It makes sense only if you do 18 children. But they grow for a long time. Even at x10 speed. Then you need a lot of pumped nannies.
Beauty and intelligence are important to a parent.