John, I never said the movie had to be a legitimate, or traditional, musical. Only a realistic one. If Kudzu wants to interpret a film through its music, I'm all for it. I WANT people to be creative in their picks.
One interpretation of realistic is that no one just busts out into song, and all music is organically driven by the plot - like in my pick, "Once."
But it doesn't have to be that way - as you and Kudzu demonstrated.
Hell, your pick is the "anti-realistic musical!" But it works as a pick because every line of dialog in that movie is sung, not spoken - so, as I said before, it is realistic in that movie's universe.