After a reply I gave to yt asking to give specifics on what they expect, they sent me this email:
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Hi,
We haven't been able to confirm that you have the necessary rights to commercially use all the video material and music from the information you've given us, so we ask that you provide written documentation substantiating your claim.
YouTube is not in a position to offer legal advice or to counsel you in any way. However, we have listed some elements below which we have seen in contracts to give you a sense of the types of documents we receive.
-explicit permission to use the rights holder’s content commercially (example: “I, rights holder’s name, give your name or channel’s name, the right to use my original content commercially.”)
-electronic signature with date (this can be as simple as the rights holder writing out full name at the bottom of the document)
Please be sure to pay attention to any limitations and/or conditions specified by the rights holder concerning your use of the content.
Once you have the appropriate contract, you can email it to us as an attachment. Please make sure to provide documentation in an acceptable format such as a pdf or image file.
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I don't even know if this is possible or if you're willing to/can do this. If not, i'd probably just purge this thread and tell everyone to try it, and if it gets rejected, there's nothing you can do about it. I have gotten a few videos monetized, but they were under 1min. Maybe yt ignores short videos during the review process.