They could have at least attempted to use more SP voice actors!

Have you not actually looked at the cast at all? All of them are Polynesian. The chief has a New Zealander's accent, which is where he is from, he is Maori. Dwayne Johnson, though born in the US, is Samoan. Auli'i Cravalho is Hawaiian. Rachael House is also a Maori from New Zealand. Nicole Scherzinger is half Hawaiian, half Phillipina, and is from Hawaii. Even Jemaine Clement who looks like a Kiwi is actually half Maori and is also from New Zealand.

*giggles like a kid* Did you really say "Irish lilt"?? How can you complain about the lack of something you yourself can't distinguish? I take offense to you saying Temuera Morrison sounds Irish mainly because he's the actor who got me to watch more Polynesian films. I was struck by him as an actor in "Once Were Warriors" (one of the most iconic and critically acclaimed films that has come out of Polynesia) and as an advocate for his people and culture. Rachel House (Tala) is also a Maori woman and that's very clear when you listen to her speak. Many Disney movies don't have their characters speak in ethnic/regional accents even if they should be, though. Did you cringe when everyone had an American or British accent in "The Lion King" "Beauty and the Beast", "Aristocats" or "Aladdin"? Those all have regional accents, but they were not used in the film.