A great idea, but I'm more inclined to get each of the people to sing the full song and perhaps later work out how to do a one-person-one-word remix.Edit: Idea! Not sure if this was your initial intention, but there are 47 words in the song; with roughly 50 muffins for randoms, you could have the video have a different person for each word and have some leeway for people who don't want to be filmed or something. Then you could also pick whoever is most on-key for each word and have the song stay roughly true to its melody. But, um, whatever you want to do is fine…after all, it is your celebration…[/fluttershy]
I do plan to get gummi worms to supplement the muffins; if people are too shy to sing they can get gummi worms instead. No one leaves empty hoofed!