I'll put most of this in spoilers as some readers may not have all the other versions of VV. However, the VV5 villagers do seem to be descendants of the VV1 villagers, many generations later. There is a lot of evidence of other tribes on the island, though.
Click to reveal..
Even in VV1 there are hints of other inhabitants of Isola, either past or present; in particular the cave shows signs of being occupied, there is a ruined temple and statue, and so on.

In VV2 two villagers find the lost children. Where did they come from? Who were the adults who until recently looked after them? Were they decended from VV1 villagers who'd become separated from the tribe, other refugees from the volcano in their original home, or were they Isola's native inhabitants?

In VV3 they find a ruined city. Who built it and when?

In VV4 we concentrate on the Tree of Life. Who were the original people who cultivated it and lived nearby, though?

In VV5 we of course meet the heathens. Who were their ancestors?

Then of course we have Biggles. Where does he come from and how does he live so long? He first appeared in VV2 and is still around in VV5 so must be pretty old by now. wink

Lots of questions, but no answers as yet. laugh confused
_________________________
To err is human; to arr is pirate.