Just looked up the Kerguelen Plateau. If it were above water it would be the second largest island in the world, half the size of Greenland and a quarter again as big as New Guinea. Looking in my atlas I see it would be a bit further south than New Zealand so possibly a climate similar to that nation's South Island but colder and harsher. Anyway, it would be cool if it was still above water.
Madagascar and New Zealand uninhabited until recently? Does that mean the colonists will tame the giant birds, or would we just have Kentucky Fried Moa instead?
One thing that can stop the Polynesians is that the BaiYue/Present day South East Asians do not lose their homeland from the Chinese thus there is no flood of refugees and fewer BaiYue will go to South East Asia who might change the status quo which made the Polynesians migrate, yes in the time that Polynesians started to explore Melanesia, the South East Asians were losing their homeland.
Sorry, I call BS on this one. The migration to Taiwan occurred around 3000 BCE. By the time of the Qin Dynasty conquered all of southern China the Austronesians had spread well into Micronesia and Fiji. There is no evidence of any migration from southern China after this time.
I am pointing out the Yue migration where in the Thais were expelled from China, at that time who also spread Rice Paddy culture in South East Asia including to the Maritime South East Asia.
The Tais were not "expelled" from China any more than the Celts were "expelled" from western Europe by the Romans. It was a gradual expansion from their ancestral homeland over centuries which apparently assimilated the less well organized Austronesians. Even today the modern day 粤 (Yue as in Cantonese) people hold genetic heritage from the Tai. And such a vast piece of fertile land won't be left alone by an organized people for long anyway. If not for the Tais it would have been the expansionary empires of the Bamar or Khmer which settle the Siam plain.