When I was a kid in grade school plays, the directors made darned sure we faced the audience and spoke right out.
Technical solutions should be WAY secondary. There's just no way anyone should have to bail out whoever is directing with "make-do" tech.
And in a beautiful, intimate theater like that you should not need any amplification.
Dick is absolutely correct here. The kids need to come to the show prepared. The adults need to understand that kids can't always pull off what is needed. Fact of the matter is you can't beat physics. 2x0=0 no matter what mic you use.
One thing I've seen done successfully with church children's choirs is to use broken mics or mics from those 3 for $30 packs to teach kids how to hold and sing into a microphone. It must be part of their rehearsal process for their entire time rehearsing (months, not just when they show up at the theater) and the instructor must correct poor usage the same way he or she would correct vocal issues.
We all know mic technique is something which must be learned. The adults leading these kids need to learn that too. If they can't then you may as well try pulling a rabbit out of your ass. You'll have just as much success.