Specifically, can we get clarification about performing known public domain songs or tunes or melodies? For example:
  • Classical music like Beethoven, Bach, Mozart, etc.
  • Old music that are old enough to have lost all copyright protection
  • New music specifically declared to be under public domain by the author

Are we allowed to perform the above? Do the above music count as performing "music of a third party" and hence a violation of the license?

Please no replies on whether enforcement is likely or not. That's besides the point. I'm looking for a legally binding official clarification on the license from Square Enix.