Are there any inhabited islands in the South Pacific?

Could people live there, self sustaining? Are there any uncharted islands left?

Uh... there are heaps of inhabited Islands in the South Pacific, e.g. Rarotonga (in the Cook Is.), Tonga, Samoa, Niue,Tokelau, Chatham Islands and technically New Zealand. There are a number of uninhabited Islands, although often there is a reason why, for example volcanic activity or nuclear testing (in the past). I don't think there are any unchartered ones, but there are some that are so remote that it may be possible to live as one of very few on an Island, for example living in the Chatham Islands. It is important to remember though, that because these Islands are all either nations in their own right, or part of a nation, that you would need visas etc to live there.