I alternated between specifically making this GM-less or GM-driven a few stages during the course of this game. I've kind of left that a bit vague at this time, because I could really see it working either way. I might need to re-read through the text to make sure I've stripped out overt references to a GM. However, you're right in assuming that each player makes a pair of mortals and shuffles them all together. Players don't know if they'll get one of the mortals they've written, or one from someone else...and they won't know if a given mortal will be a ward to be protected, or a troublemaker needing to be dealt with.
Thanks for reading and offering a comment.