1) you wouldn't go the fingerprint route until you have scale.
2) if you have scale, you'll say, hey, lemme fingerprint your whole library so we can automatically handle this for you.
3) I'm 99% a company sells this service, I forget the name.
EDIT: found this: https://tunesat.com/tunesatportal/home
This sounds like an interesting problem. Somehow, buy borrow or steal the top 10,000 (?) tracks on spotify so you can finger-print them.. hmm probably more like 100,000 tracks.
But yeah, your co-founder better be a lawyer.