The music seems original. I can't find it being close to any of the character theme music to have a connection i'll reiterate my theory:
MF keyblade supports the time travel idea heavily. If MF is the antagonist of 3D he could very well
could bring the future antagonist into the KH1 world like the nobodies, Org., Dusks, and more against Sora, and Riku. The idea that if Sora, and Riku could defeat MF to get the No Name keyblade could relay to possibly being able to save TVA by the time travel....But KH1 Sora, and Riku don't know about the letter at the end of KH2/Reconnect.