I understand your point, but not too sure where the true seperation comes in with pitching coaches and their philosophies.
None of the coaches that son played with while growing up were involved with the NPA, (that didn't exist back then?) However, many of them did have philosophies similar. To me, the NPA is just a philosophy that should be adopted by all, training, throwing frequently, pitch count watch, reguired rest, etc.
No pitcher, regardless of who he is will ever escape an injury. Mine also was healthy all through his early years, I attribute that to being smart and not overuse at a yong age. However, recently had a setback but nothing major. Labrum fraying, happens to all pitchers, and not necessarily an issue, but bothered him.
I made my comment about pro ball because there are many different philosophies for pitcher use, some pitch every 5,6 days, some every 3 or 4. Lower pitch counts, higher pitch counts. You'll find that in college also. But I agree the object is to make it to college or beyond healthy.
What we did, was inquire as to pitcher use, that was important. My son's pitching coach was not a huge fan of complete games and you get pulled regardless of a no hitter or not, etc. Depending on where your pitch count was and if you showed signs of fatigue. That means the pc has to be pretty in tuned to each individual. I am not a big fan of just pitching every 7 days in college. I also liked a staff that has enough pitchers to get through the season and uses them and you will not find that everywhere.
You will find that most good pitching coaches know their stuff, the more successful the program the better he is knowledgable, though there are many programs that each and every year in the running, but do not manage their pitching staff well. Take note of pitcher use including pitch counts in games and team ERA, etc. if that is important to you.
That is the first thing that should be considered, regardless of philosophy.
Good luck.