With the OpenScore site. Individuals purchase the rights, they refer to it as 'Liberating Music". You're not going to find Billy Jean by Michael Jackson. It's mostly classical music and music used to teach lessons. But the age of it fits with FFXIV.

If I'm understanding your comment, as long as there are not restrictions on the license that prohibit public performances it would be acceptable?

Would a player then just provide a link to the license for review, if asked?