This is now canon. You can assume your characters know all of this, as a result of talking to Ulantanu or the hanging merchants about the model of Zyan above in the Temple of the Archons. http://maziriansgarden.blogspot.com/2017/01/zyan-above.html
This is now the canonical version of the book of poetry you recovered, In the Light of Other Moons. It differs in some ways from what I said before. Especially relevant to Aleksandr Revzin and Chris P.
Some doctrinal disputes among the followers of MANA-YOOD-SUSHAI concerning the nature of the dreamworld and its relationship to the waking world. Of special interest to Eric Boyd
This describes the current base of operations for the party. Anthony Fournier The second hook is no longer relevant ;). I will post new campaign need and update the equipment lists tomorrow.
This blog post contains some of the information you extracted from your interviews with Ulantanu. It contains a bit more, which has come out in further conversations. I will put up a blog post soon with information about the guilds and drop it here when I do.