Great questions! I am new to Esteren and have only run the dream sequence scenario in Book 0.
I honestly thought there was more information on the Feondas than what has been presented here. But I can see that is not the case.
This my take on the Feondas and Flux (at least until something official ...

I am looking for some screen background/savers for Esteren. In particular the 1920x1080 resolution size. It would also be nice if there were also some Facebook banners I could use for my group when I run Shadows of Esteren games. Anyone know where I can find stuff like this?