Yeah little Kel is working for Kellhus as is everyone pretty much. I even half think that theo is playing charades making it appear she is more skittish than she is. there are points in the books where little Kel thinks she is scrutinising him.
Kellhus tells Proyas he still has some resources in the New Empire, clearly not referring to Maitha (it's after he explains that Maitha and Esme are at odds).
Interestingly, lil Kel reveals he has been conditioned in his final scene in WLW. We only get his exterior dialogue, but he's telling the voice how things are going with the ordeal. He describes how the Few are culling sranc with exactitude, then...
"Father told me. In his own words, he said, "This is how it will happen, Kel."
...
"Well, mostly in his words. Some of my words too."
...
"Secret words - he even said so. Words that no one - no one - can hear."
"No. He never told me to kill anyone But then, why would he have to? The words were secret..."
So secret that even the inner voice is unaware of them, after counciling lil Kel to be so careful around big Kel? Wheels within wheels.
Imagine the shit storm that little bastard will unleash if/when Esme is killed.