I love this game and the story. I hope v.19 comes out soon, I want to know more if what is going to happen in it. Just curious though, humans are actually the aliens to that world and didn't really evolve there, right?
Well, not exactly aliens since it was stated in various places that Elves, Faries and Humans did have a common ancestor. Though how those 3 major species have diverged that much is still unknown. I would also argue that elves and faries are probably closer related compared to humans, but maybe humans evolved out of elves? It would take a really long time of strict isolation for such a strong diversion. That includes the various elf races.
It's theoretically possible that a prior highly advanced civilization was responsible for spreading some "farming animals" across the various islands where they then evolved into the species we know now. That old civilization may have left the planet or simply went extinct. This may tie into the religious background (Gaius, the seeder, etc). But up to this point there isn't much known about the origin of the major species. So far we just know that they are related.
I had read that in the have dialogue, but I was thinking that because the continent the story takes place was primarily elvish and fey, I felt that there could have been more races on the other continents and humans came along and wiped out each of them. About what you said about the Seeder and those other aspects of the religions and the old takes, I think you are along the right track of seeding the races. It would be cool to see other races that didn't exactly for out but went into a kind of hiding, disguising themselves among the human population. I wonder if we will get to see the Capitol and its continent in another game after this one is complete.