Just spitballing an idea. Along the lines of airdrop, does the instructor have a machine that the kids can send their music to when they’re done? This would create a backup, which the instructor could then organize and upload to a server (google drive?) that can be shared with the iPads as read only, so the kids could redownload the file again if need be.
All I can think of is one of Mr. Lovenstein’s comics… we’re finally free now!