What is Cthulhu doing in the Necronomicon?? (Patreon)

If you read Lovecraft's foundational short story The Call of Cthulhu, you will come away with the impression that the Great Old One and his cult are not mentioned in the Necronomicon at all. The text reads "No book had ever really hinted of it, though the deathless Chinamen said that there were double meanings in the Necronomicon of the mad Arab Abdul Alhazred which the initiated might read as they chose...". 

Yet in The Dunwich Horror we have an actual quote from the Necronomicon stating "Great Cthulhu is Their cousin, yet can he spy Them only dimly", and in At the Mountains of Madness the explorers recognize the Spawn of Cthulhu warring with the Elder Things in the murals, based on their reading of the Necronomicon.

How do we reconcile this? Well, obviously as Lovecraft added to his mythology he wanted to incorporate more details and include them in his favorite Tome, probably not even remembering that minor plot point from 1926.

But can we square this within the fiction? The answer for me is yes, and the method is simple. In The Dunwich Horror, Prof. Armitage translates directly from the Necronomicon. In At the Mountains of Madness, we are told that Lake, Danforth, Dyer, and Pabodie have all read portions of the Necronomicon. But in the Call of Cthulhu, neither Francis Wayland Thurston nor Inspector Legrasse actually have access to the Necronomicon. In fact, it is Old Castro telling Legrasse what the Chinese cultists had told him about the Necronomicon! That is quite the game of telephone.

As a final note, Lovecraft states in the outline "History of the Necronomicon" that Abdul Alhazred "was only an indifferent Moslem, worshipping unknown entities whom he called Yog-Sothoth and Cthulhu."