It all depends how much support the league officials give to the umps. When my sons were in LL, the Minors used "volunteers" (read: Dads dragged from the stands). Another qualified ump and I finally (after a few years of offering) were given the okay to use Sr Division playetrs, plus Major managers and coaches.
The managers/coaches had to ump at least one game per half. The Seniors worked according to their availability. We had the league purchase enough rule books and umpires' manuals for all. There were four classroom sessions, plus one on the field to cover mechanics. They had to pass a rules test at 80% or better.
The league informed the Minor managers and coaches that the youngsters were to be treated with respect, or they would be admonished, and possibly suspended. There were NO problems. One of the reasons was that a BOD rep attended every game.
Bob