Potentially new(ish) info??
From The Lost Media Wiki
Hi! I was scrolling through the Disney Wiki and found a link to a forum from someone that went to a private screening of Musicland. Apparently there's a guy in Australia that owns an original 35mm Techinicolor print of it, but he is hesitant about releasing it because he doesn't want Disney to come after him. Anyway from what the person said is that aside from the title and credits there weren't any new transitions made for MusicLand. Anyways here's the link to the forum: https://forum.blu-ray.com/showthread.php?s=9f8f025473c61f1f09ef8b431a1551ee&p=11124187#post11124187