To be clear, I'm not suggesting that the Aborigines are going to form armies in the tens of thousands and push the Maori back into the sea. But they were capable of matching the 1300s-era Maori in organisation and (approximately) military technology. .
The Polynesian do appear to have better military technology.
http://www.mythichawaii.com/weapons.htm
The other issue that is puzzling is that the Maori people dropped the sling. Which is puzzling as the Polynesian did have and used slings in warfare. The POD did call for a Polynesian Australia so it is quite likely that these people had slings too.
However, without the sling, I would say that the Polynesian do have significant better military technology.
Centuries later, to be precise.
They weren't going to build up from there to generals and forts for quite a while.
The expedition to get there would have had a chief and I am sure that they would have put up forts almost immediately particularly if the locals are hostile.
Yes. Key point here is 1860s. The entire Maori population wasn't 4000 people in 1300. Or even in 1400, based on the most likely population growth rates.
Agreed it would be scattered settlements. Early settlements appear to be between 30 and 400 people.
Amusingly enough, based on what happened in OTL Australia, ATL Maori colonists would be facing the same problem that the British colonists faced during the Maori Wars combating guerrilla warfare :
The British did not face much guerrilla warfare in Australia, it is rare the Aborigines united, not being tied to the land, it was possible for the Aboriginal bands to move, the Aborigines knew they were outclassed with the "bang bang sticks" so the fighting was fairly minimal.
against an opponent who knew the land much better than they did .
This would be true only at the start after say 20 years both know the land equally good.
I'm not sure why. Based on the size of early Maori settlements, they would not have been large enough to field more than 100 warriors (probably less). The Aborigines were easily capable of matching that.
The Aborigines might be capable of matching that with an exceptional leader. If I was to bet on 100 Polynesian warriors vs 100 Aborigines, my money would be on the Polynesian.