I have the book but never used, I have my hands full with Emer now.
First, most of the books with Shadow World stamp were designed as stand alone adventures and it seems ICE allowed writers to fit their small worlds in the big Kulthea picture. Think of Forgotten Realms.
The only canon is what TKA wrote plus approved, and part of the canon is that there are many local gods, so the Elder Gods could be from Orhan, and the rest (Dead Gods, Law & Chaos, others) are a mix of local Gods plus the traditiona Orhan and Charon. I would fit them in the character that fits them better (Moren could be Shaal, Hottr could be Oriana, Gwyne could be Phaon and Besida one of his lovers, a powerful spirit...), just make it work.
But I remember the topic and I thin for me it was quite clear, so I will fill the undetailed parts with some assumptions. Thosque has a caste system based on Ramonth teachings and this is written in the big temple of Rasul in leafgold, also everybody knows that the original text in the library of the temple.
But how about if a cleric that belongs to the lesser nobility was researching some documents and found a copy that says nothing about castes and nobility, and after some text analysis spells, he knows that it's from the same time than the original text in Thosque. But as everybody knows too, there were two copies of the original document, one in Rasul and one stored somewhere in Arelios, home of one of the heroes.
If you want to check the theological aspects it could be that Ramonth is a dead god too and his role was filled by the greedy Pylon, so he has two aspects now.
Hope that helps.
