The key term here is "based on." Sure, Alola is definitely based on Hawaii, but that doesn't mean every Pokémon has to fit with the Hawaiian theme. Look at Unova, the region based on North America. Yes, it does have Pokémon based on eagles, buffalo, pheasants, bass, and ice cream, but it also has Pokémon like:
- Sigilyph, which has a very Egyptian appearance
- Serperior, who's design is basically a snake covered in a French fleur-de-lis
- Blitzle/Zebstrika are zebras, and last I checked zebras were from Africa
- Cofagrigus is an Egyptian sarcophagus
- Archeops, based on Archaeopteryx, which was dug up in Germany
- Golurk is based on the golem in Jewish folklore.
My point is, while a region can be based on a real-life place, it doesn't have to adhere strictly to that place. While Alola does take a lot of inspiration from Hawaiian culture and seafaring in general (the Tapus, Dhelmise, Alolan Raichu, Alolan Ratatta, Wishiwashi, Yungoos, Primarina, Alolan Exeggutor, Alolan Marowak, etc.) it also has elements of other cultures and locales, such as Komala, Oricorio (the Galapagos), and Lurantis (orchid mantises are found in Southeast Asia, not Hawaii) to name a few.
TL;DR Just because a region is based on an actual locale, that does not mean that every single Pokémon has to be based on an actual thing from that area, as has been shown in the past.