As someone who's experienced the attraction, here's what I have to say:
The queue was very similar to the GMR, same red ropes and Chinese Theatre wallpaper, but they gutted every movie prop showcase to essentially make one giant room full of switchbacks.
The preshow is very cute, Mickey and Minnie going on a picnic, Goofy crashes into the screen creating a hole and smoke for you to walk into the cartoon.
From there the attraction sort of falls flat on expectations. The 2.5 D is honestly amazing, but the actual movement of the ride is similar to Pooh's Hunnyhut. Like Rise... but a lot slower. The AA's are pretty lackluster. Essentially small body figures with no animation and flat faces for the projection mapping.
The Daisy dance room scene is a cool effect in terms of ride vehicle movement, but the AA is very disappointing and the room itself is not much to look at.
As far as the theme song, it definitely has a song but as far as I recall it was only sung in the preshow and not used anywhere else in the attraction.
Overall enjoyable, would definitely ride again to take it everything, but not a worthy replacement of GMR.