Right now as we develop art and lore for Crixa, it crosses over nicely with Ember. Since Ember is early on and mostly in design and art stages without coding, the work is compatible. When Crixa is ready for its KS in 2-3 months we will expand the paper and pen writing staff to handle fleshing out the content for the paper and pen RPG.
Ember art is handled outside of myself (I only direct the art in a general way), its working out pretty well so far.
As for FF, I don't think its a good idea for me to continue to speculate on the the whys and wherefores.