>>32901350
>>32904075
For the record, I've seen derivative works that use official Touhou assets; Genius of Sappheiros, for example, uses bomb and extend sound effects, and there are countless fan videos on YT/NND that use official sounds, visuals, and music. To my knowledge, the only precedence for ZUN taking down projects with official Touhou assets is YouTube uploads of the music CDs. Not even the game OSTs, just the music CDs.
Anyways, honestly I wouldn't be too worried so long as it's free of charge. I see mods and other fanworks use Touhou music, both official and derivative, all the time without any complaints from the original creators. Good on you for crediting them; maybe throw in links to buy said works if you want to go the extra mile. In case anyone were to get upset about it, I think switching the song in question for another one would be enough to satisfy them, and as others have stated a C&D is probably the worst case scenario.