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.
Noting a correction is part of a larger scope of annotating something. From Wikipedia:
Aristarchus of Samothrace was from c. 220 – c. 143 BC, so it’s been used for notation since at least then!