bdn223 said: "Lin will not make the same mistake that the Lopez' did when they let Disney convinced them into somehow reworking Let It Go from being the end of the first act of a 3 act film into into being the Act I closer of a two act musical."
This would've been Jennifer Lee's "mistake," not the Lopezes, as the song itself remained mostly unchanged from a storytelling standpoint. And she might not have had much choice, if it came from The Mouse. Though Lin might be in a slightly more powerful position because of his name recognition, and because he has a story credit on the film (and therefore might share some book-writing responsibilities).
But in any case, I think it's moot, because I don't it's a comparable situation. "Let It Go" occurs 30 minutes into a 90 minute story (the end of the 1st of 3 acts, as you said), whereas "We Don't Talk About Bruno" occurs almost exactly halfway through the story.
And as for a "what's next?" moment. If I remember correctly, doesn't "Bruno" end with Mirabel putting together the shards of the prophesy, and seeing herself in front of the breaking house? A reasonably significant "reveal" in the plot. So there's your "what's next?" moment!