Pleased to see a new memebr, particualrly one who aims to teach kids.

If you plan on reloading disposables, check out this path in advance.

The few that I have played with reloading use a standard 35mm cassette, but it has a non standard central spool.

One end of the spool has a one way ratchet style coupling to mate with the edge of the film advance thumb wheel.
So you need to reload onto that spool. This could slow you down in terms of relaoding a whole class worth's of cameras one night.

Otherwise I wish you all the best with your education project.