As we know that all practicing sorcerers (bar Cishaurim) seem to be damned, does Inrau's unexpected use of sorcery for self defence just before the end of his life damn him, despite his choosing of priesthood over sorcery?
Welcome to the Second Apocalypse, Dracostar.
I think other's have covered the inquiry to the best known rationale.
On the Ciphrang thoughts upthread:
Fall upon them! the Voice screeched. Rend them! Only in their midst will you be safe from the Chorae!
...
Setmahaga fell first, struck in the eye by an absence affixed to the end of a stick. An explosion of burning salt...
Flee!
Then Sohorat, his slavering form caught in torrents of light, screamed.
Weak...
There are others, the Voice said. Far, far stronger.
Perhaps I will die.
You are too mighty.
Perhaps you will die with me... Iyokus.
And in the end it grovelled beneath his song, cringed like a beaten animal, then faded into blackness...
As far as we know, the Chorae explicitly seems to permanently change their state (as per the Voice and the Salting?). Why sorcerers wouldn't just summon Ciphrang they were done with and Chorae them, who knows? Maybe, they do and the Scarlet Spires practice a strict disposal policy so that only mistakes or lack of skill get Schoolmen damned by Ciphrang.
Also, seems to indicate that a powerful enough sorcerer can "kill" a Ciphrang (implied by the fear of the Cishaurim - the one Ciphrang seems to have been attacked beyond his ken - and if anyone kills one by sorcery, it's Achamian in TWP).
So... the definitions remain pretty much up in the air still... Lol.
Is it possible that Onkis could not intervene as she did not recognise the threat of the skin-spies, considering they lack a soul? I believe Maitha stated this was the same reason the Hundred could not comprehend the No-God, which was why they considered Kellhus a demon.
Curethan, I think, is referring to this quote, which some of us think satisfies preceding conditions for Divine communication, especially after the Revelation of the Gods in TAE:
The small scroll clattered to the floor. The silence was complete, oppressive. His heart ached, so much was at stake. These were the events upon which the world turned. Enough for a Goddess.
"Please... Speak to me."
Nothing.
Tears branched across his face. He raised his arms, held them open until his shoulders burned.
"Anything!" he cried.
Run, his thoughts whispered. Run.
Such a coward! How could he be such a coward? Something behind him. The sound of flapping wings! Like the flutter of cloth among the towering pillars.
He turned his face to the shadowy ceiling, searching with his ears. Another flutter. Somewhere up in the clerestory. His skin prickled.
Is that you?
No.
Always doubting, why was he always doubting?
As far as I read it, we know that Onkis specifically is the Goddess who come before men in their thoughts. Onkis might not recognize the skin-spies but she'd recognize the simulacrum of Aurang in the Synthese. Inrau's own doubt of Inrithi metaphysics dooms him to misinterpret obvious communication from the Goddess

.
[EDIT: I know Duskweaver's pointed out the "branching tears" but anyone notice the "flutter of" metaphor as Inrau first hears the Synthese's wings... Thinking of the Cishaurim showing up the Scarlet Spires.]