There seems to be a lot of confusion regarding the theming in relation to Animal Kingdom.
Attractions at Animal Kingdom should be primarily about animals of the past and present, and of the mythical. There should also be a theme of conservation and not over-exploiting resources when it comes to nature in the present day.
Many of the attractions have a sense of adventure to them, this isn’t at theme, it’s just a method to make sure it’s edutainment rather than just education(as adventure triggers a sense of excitement and fun). So you can’t make a ride of the base of adventure, as it is only an addition to enhance rides.
Good aesthetics are crucial in creating a good ride, but it doesn’t mean correct themes, they are just used to integrate themes into lands.
So, onto how certain current rides and rumors of new rides fit or don’t fit those themes:
Dino-rama is only there as they needed extra attractions but didn’t have much cash - for the funds they had I honestly don’t think they did that bad. But anyway, this area should be scrapped, but not the Dinosaur theme, as it’s a key part of Animal Kingdom(the fact that it’s animals of the past and it shows that one major event can be catastrophic to ecosystems - highlighting the effects of things like global warming may have in the future).
So, Indy on his own can’t work. It may possibly be able to retheme Dinosaur to maintain it’s major theme and include this major IP, but the ride is already popular, so that’s fairly useless. But it’s most likely that Disney would just not care and shove in a South America area, with an Indy ride and the rest of the land that doesn’t fit within Animal Kingdom.
Expedition Everest provides a major thrill, which is required, while satisfying the mythical aspect of the overall themes - it fit.
Pandora is the perfect use of IP within Animal Kingdom. The attractions within the land don’t really represent the themes, they just satisfy the need for fun and amazingly themed attractions within the land. But Avatar is really not even about the mythical aspect, but the present aspect. The moon Pandora quite obviously represents Earth; everyone sees how there are aliens and assume it’s just sci-fi, but it’s so Earth like that you may as well call it Earth. The only things that aren’t Earth like are the banshees and the interconnection between every living thing.
So, the themes of Avatar are to respect and not exploit nature, and conservation, as this is really about Earth, we can just say that these themes relate to Earth, and so the film is perfect for Animal Kingdom.
The rides don’t directly relate to these themes, but it doesn’t matter, as there is a sense of these themes present in the land, as everyone there knows the film and relate the rides to them.
Mystic Manor would fit aesthetically, as people have stated, but, as previously stated, good aesthetics doesn’t mean correct themes, they are just used to integrate themes into lands. So it wouldn’t fit in it’s current state, but that doesn’t mean they couldn’t change the storyline enough for it to work, but knowing Disney, they would just want to copy the ride straight to Orlando, in which case it would make much more sense in Magic Kingdom.
That’s it, I think.
EDIT:
Zootopia wouldn’t fit, as they are just anthropomorphic animals playing out entirely human situations, it is essentially a human story, just like Avatar is really about nature on Earth.
People tend to ignore underlying themes. Zootopia has nothing to do with animals, other than that characters look like them. People see that and assume it should go straight into Animal Kingdom, it shouldn’t.
People see that Avatar has big blue people and is set on another world, they see that as the theme, and don’t look beneath that(I say beneath that but it really is quite obvious). It’s entirely about nature on Earth, and respecting and conserving it, so fits in Animal Kingdom.