It's a weird thing to break down because Disney is so wildly inconsistent with their theme park show quality. Some are incredible, some are good, and some downright suck, and what's funnier is that budget doesn't seem to come into effect for any of it. I honestly think they just throw everything at a wall and rather than seeing what sticks they just blindly grab at whatever is leftover and implement that.
Now, I worked as Production Manager and Tech Director for a 500-seat professional theatre outside Philly a few years ago and we operated on very tight budgets as we were non-profit. We still put on Beauty & The Beast, Newsies, and other large-scale shows to rave reviews. Most of the time my set budget was $5K, sometimes it was only $2K, but I never had more than $5,500 to play with for the set. Costumes, lighting, and audio all had less budgeted per show, so you can imagine the kind of money we were working with. I designed a three-story set for Newsies, a 40-foot by 20-foot rolling house (with a second floor!) for A Christmas Story, a multi-level MC Escher-inspired set for Next To Normal, etc, all on less than $5,000. The $5,500 came when we said screw it and rented the castle set for Beauty & The Beast, haha. My point is people can make excellent, fun, compelling entertainment for very little money. Disney, on the other hand, has money to burn and they still manage to be all over the place in terms of quality.
The Lion King show at Animal Kingdom was fun because it was trying to be fun. The Little Mermaid I can't give an honest take on because I've not seen it since I was maybe 12 years old back in the mid-90s. Beauty & The Beast's show next to Tower of Terror was middle of the road but still definitely on par for a theme park revue. Frozen failed, IMO, because it tried to tell the exact story from the movie in 2/3's of the time (60 vs 90 minutes) rather than truncate it to a manageable narrative. Aladdin did it wonderfully. They still had all of the hits, all of the humor, but it was 45 minutes and the audience was satisfied. Frozen is 60 minutes long and sucks because it's too confused for its own good.