Outfielders - 8U coach pitch

Question
Local rule:
A team may field 10 defensive players: four outfielders, four infielders, one pitcher's helper, and one catcher. The tenth fielder must remain fifteen feet behind the baseline until the ball is put into play.

My question is this... Since the local rule does not address the remaining 3 outfielders as far as # of feet behind baseline, does the umpire control this?

Specifically because we (local board) have been told by a coach that he can send the rest of his outfielders to the infield if he wants since we didn't address them. ASA does not address this age level as far as I know and I want to make sure we handle the situation correctly, either instructing the coach as to the umpire's right to determine or addressing our local rules.

Answer
Since you have a coach that is not interested in the spirit of the game you will need to adjust your local rules.  The umpire can not enforce rules that are not there.

If you have a rule that states the the 4th outfielder must be in the outfield, it only makes sense that the other ones need to be there as well.  Unfortunately you have a coach more concerned with winning than teach the girls how to play the game.