I figured I'd ask in case anyone knew/found out in the last...few years. It's a waltz played by a concert band, featuring what sounds like French Horn...the melody has a carnival-like sound, vaguely like "Caliope Carousel" by Roger Roger, though not the same.
YouTube ID 2QOhySd-QwY [embedded below if that's okay] - it's not the actual piece that plays in that scene