Why is Moana actually needed for delivering the heart?

Question

In Moana the plot is about a main character (Moana) who is returning the heart to Te Fiti to... well, prevent the world's end. Here's the order of events:

• Long before the story Maui steals the heart and loses it and it falls into ocean water.
• Then when Moana is a child the ocean pushes the heart to the island shore right into Moana's hands.
• Moana is immediately distracted, so her grandmother takes and stores the heart.
• Moana gets older, the island is in danger, Moana takes the heart, goes to find Maui, they together return the heart and the ocean is assisting Moana all the time.

So basically the ocean first delivers the heart to Moana, then accompanies her all the way to Te Fiti and keeps assisting her all the way.

Why coudn't the ocean just deliver the heart to Te Fiti instead?

Answer 1

According to the legend, it was implied that Maui, who stole the heart, had to put the heart back. Maui had no interest in doing this. The ocean chose Moana to convince Maui because it could tell she would be curious enough to entertain the oceanic travel her tribe (and likely other tribes) abandoned, and she had her water-worshiping grandmother influencing her.

Maui did try to deliver the stone, but he did not realize the lava monster was the island without the stone.

The ocean, being the natural water enemy of the lava monster, might not have been capable of convincing Tefiti to calm down long enough to accurately place the stone back.

It took Moana to put two and two together and conduct the act with appropriate communication in a calm manner. Moana just happened to be there to do this, as her implied job was to escort Maui. She instead inspired him.