4) Prediction: The Nonmen will find a way to continue their race.
Explanation: These guys have two variants: join the Consult and restart the damaged world or join the Emperor and fight with aliens. Of course, the Consult can promise them a lot and we know that many of them have already been serving the Consult. However, they will choose the Emperor, if they will find the way to reproduce.
What if Serwa can conceive and bear a hybrid? After all, she is a genetically modified, super-hot witch. And I suppose that Anasurimbors may have genes of the Nonmen.
My second theory has no proves at all and it cannot stand against Occam's razor. However, what if Sorweel can bargain with his goddess. Yatwer is the goddess of fertility. Maybe Yatwer can somehow stimulate ordinary women to bear the hybrids. In this case, Sorweel will become an enormously valuable subject of bargaining. Maybe he is an intermediary between those who suffer from a lack of ability to reproduce and the goddess of fertility. Gods wish to destroy Kellhus. Why not use the Nonmen, hitting at their weak point? I know that this is nonsense, but I am sure that Sorweel will play a great role in future.