Multiple versions of songs would be less of an issue if when posting a re-harm or alternate version, members would include some source information or description:
"here's my own version using different changes” or "as performed by <artist name>" or "from Vanilia Book 3” etc.

When possible include a brief descriptive label in the chart's song title too. That helps members identify different versions in their libraries.

When a new user searches for a title and is presented with several choices, the additional info is helpful.

Thanks for sharing
)BOB