The moment I saw that the dragon had those antennae/bunny ear looking bits, I knew it was Hilary and the bitch in the armor was that witch lady. The fact that no one who has been reading the comic since the start of the arc picked up on this "twist" just goes to show how fucking brainless Phil's reader-base is.
I mean, the witch didn't even bat an eye at Art, Kat or Pip, the Dragon explicitly goes after Kat first, the Dragon reacts negatively to Pip's comments regarding Hilary and the Dragon, and there's the biggest fucking hint of all:
THE WITCH BITCH LIKED ART'S FIRST DRAFT. She still had suggestions for improving it, but the fact that she loved Art's initial draft, compared to his usual clientele, like Hilary for example, was a big fucking tell that this was not in fact Hilary we were dealing with.
Jollyjack can spin a good yarn, but good fucking god, too fucking many of his viewers are morons.