I like the idea of "John the Dunker" rather than the Submerger. It ties in also of course with witchcraft trials, at least in the U.S.
The original Mystery Plays always make me uneasy - I keep thinking of adjunct stories like Chaucer's Little Hugh of Lincoln and the damage they did, not to mention current sectarian violence around the world.
And I felt a bit uneasy with this story, of course told ultimately by the victors; as far as I know, Josephus doesn't mention it, so there's a blank slate, something missing, etc.
Why did you leave
'Render unto Caesar that which is Caesar's.' and some other passages in the language of the King James? Just curious.
Great series, this one making me uncomfortable!