As near as I can tell, Moana isn't a magical story about a Polynesian girl going on a journey of self discovery in order to save her people from an encroaching darkness that kills all life. It's a story about transhumanism, humanity visiting the stars, and how super human AIs can be a huge problem.
The reason why I can't accept Moana as a magical story about Polynesian island hoping is because of the timeline that Maui performs all of his works. Why does an eel buried in the sand form coconut trees? Who cares it's magic, but the important thing is that he didn't provide coconuts to humanity until humanity had already threw him out into the ocean. He provides fire, moves the sun, raises the islands (! where was everyone before this? just floating in the ocean?), etc. His works are basically required for humanity to exist on these islands, but the works didn't happen until after humanity was already around long enough to case him out.
The rest follows from there. Super human AIs are possible, but relatively rare and apparently come with built in limiters of some sort. Te Fiti is a super human AI and her heart is some sort of module that regulates her more extreme abilities. She becomes Te Ka when she loses the heart which feels a lot like some sort of "safe mode" that prevents any additional tampering with the AI after it has lost it's heart.
The ocean is also some sort of super human AI, but also has some extreme limitations built in. The ocean could have easily performed the entire quest that Moana goes on if it were some sort of magical spirit of the ocean thing. It's massive, it has the heart, it has the ability to harden Te Ka. Just splash up on Te Ka and place the heart in her and bam the story is complete. However, if the ocean is some sort of AI that isn't allowed to attack other AIs, then suddenly things make a lot more sense. Built in restrictions are why the ocean can't return the heart. Built in restrictions are why the ocean doesn't help Moana except in incredibly minor ways. It doesn't help in the realm of monsters and it doesn't help in the battle with the coconuts.
So what are humans? Well it's the far future and we have all these space ships and super advanced software tools that people can use, but space travel isn't really for the human psyche. Waiting thousands of years to get from star to star isn't really for people. Additionally, nobody wants the AIs just doing whatever they feel like (hence the restrictions put on the ocean and Te Fiti). So humans are likely simulated humans that are unaware that what they are seeing is a massive metaphor for space travel. The islands are random gravity wells (moons, planets, asteroids). The boats are space ships. The food is fuel and other raw materials. This allows people to direct the future of humanity without yielding all the decisions to machines AND it allows humanity to survive floating around in empty space for thousands of years at a time.
Maui is the first to undergo this process. Humanity on Earth cast him into space with some unusually powerful hardware and software, and off he went to "terraform" the space ways. Setting up fuel depots, space elevators, solar cells, etc. It is interesting that Maui is stuck on an island for "1000 years", but when he is confronted by Moana on the boat with the heart of Te Fiti he immediately jumps off the boat to swim away. He didn't try swimming for it before because he was stuck on a planet. He could try swimming for it once he was on the boat because the boat was able to get him into orbit where he would have been able to drift to another planet with sufficient infrastructure to built his own space ship.
The monsters encountered are either rogue AIs or humans who have modified their mental states. People reincarnate/turn into ghost thingies is actually them becoming mentally exhausted with their journey and being retired into an "afterlife" where they no longer have to unconsciously direct a bunch of AIs. Moana's visions are actually some sort of interface into the universal internet. And the songs are actually some sort of more in depth interface between two individuals. Maui dumps a lot of memories on Moana in song form and he states that he'll throw up when he thinks Moana is going to sing (indicating that he is going to reject a song sequence request if one shows up).
So far the whole movie makes a lot more sense to me when viewed in this light.
