Isn't there confirmation that the Tusk was introduced by the Consult as a tool to kill the Nonmen?
I don't know. There's a reference in one of the Sorweel chapters in TGO to a "tutelage of the Vile", but my understanding of that was that it was the Consult teaching men Anagogic Sorcery. I do believe that the Tusk (and the Later Prophet's injunction to kill sorcerers) were Consult/Inchoroi tools, but I don't think that's been established.
To me, I am very doubtful that the Solitary God exists. More to the point though, I do not believe that the Solitary God exerts any influence in Earwa. The SOlitary God's "power" allegedly comes in the form of Water through Cishaurim, but we know that isn't actually true. Moe had water and sure doesn't believe the Solitary God works through him.
Where does the Psukhe come from, if not the Solitary God? If it was just another type of magic (like Gnosis/Anagogis/Diamos/etc), then why didn't the Consult know anything about it? Remember, they thought the ability to recognize skin spies was a part of the Psukhe, which implies they have no idea what it does. I suspect that even if the Psukhe isn't divinely
powered, it's at least divinely
inspired. That is, the first Cishaurim were shown/taught the Psukhe by the Solitary God. Otherwise, why would it only show up among the devotees of the Solitary God?