Somewhere, IDK if I still have the link or not, but it was a very long article about a number of R&R muscians from that era that either attended military schools or were raised in strict military families. Stephen Stills, Frank Zappa, Morrison, David Crosby, and 'Mama' Cass Elliott, are the names I recall. And if I recall correctly, Crosby and Elliott knew each other from school.
If I can find the link, I will share it.