If it were someone specifically from the island of Tahiti then the answer is Tahitian.
frock
goblet
A Turks Islander.......
Simple, Islander!
I would call them islanders.
Try the word Flotilla.
a staten islander
a rhode islander
Because there are many glaciers and volcanoes there.
Call Letters
The answer would depend on what you call a civilization. If you will call a civilization. If you would accept a city, the first place would be Dwarka, which is dated back to 32,000 BC. If you want an entire empire, the oldest is the Rama Empire, 15,000 BC. The Ainus of Japan are next, then the Pacific Islander Aroi Kingdom. Mesopotamia would be far from the oldest.
what we call ourselves has too have a e in it and five letters