To finally respond for anyone in the future looking to solve this...
You can either use the false tree of the animation to stop all sounds which I think should still suppress sounds embedded in the animations, then use the appropriate events to play your own at the right time OR...
Looking at the files in a hex editor there is a sound.(filename) declared in the animation data. I suspect if you zero fill the filename it will just ignore the missing sound, however it may be more desirable to hack in a sound you're actually looking for. I think this was done to better sync sounds with animations (particularly in superstar, where you want the dancing to match the music reliably). You would then want to rename the animation as a custom one. I have not actually tested this, but it would be the place to start, probably.