For the human population, what about Kuro's people?

I also think that there should be more people in the independent villages/confederacies, because the Garakai keep talking about how they want to crush the southern tribes. I think some of Rtron's posts mentioned them being rather numerous but also mostly a bunch of peaceful farmers and poorly defended villages. Perfect for Garakai to conquer/enslave and for Ialu to "save" and "enlighten" with his teachings about the Mighty One.

In any case, assuming that the southern tribes makes up the majority of those 1800 humans, that's still something like a mere 1,000. That's just like five or six little hamlets, not really tribes.