I must admit that my knowledge of Polynesian history is not great, so of I get anything wrong, my apologies.
I'm amazed that these islands were even colonized in the first place without modern technology. But it makes me wonder how much contact/communication there was between islands when such long distances are involved.
There was a lot of contact between tonga, Samoa, Fiji way up too European contact and even after European contact.
Less contact between Tahiti, Hawaii, and new zealand but it still happened.
Tahiti was the center of Polynesia after the 2nd great migration of the Polynesians. and there are stories from New zealand, hawaii, and tahiti of voyagers traveling back and forth between the islands .
Eg. (New zealand) sailing back to tahiti to get sweet potato etc etc Another one was the sailing reggata in tahiti
(Tahiti, Hawaii) "A number of chiefs from islands named Ahu and Tuhua visited Hawaiki (tahiti) and boasted that the men of Hawaiki could not equal them in canoe racing. [Percy Smith (81, p. 97) believed that Ahu was Oahu in the Hawaiian islands
There are many stories of voyaging back and forth between the islands but it sounds like it stopped very quickly.