Watching with interest.
My gut tells me that freely pivoting fins will flutter, essentially wandering back and forth in rapid fashion searching for equal pressure on both faces of the fin. I have visions of the Bullpup (audibly) buzzing through the air and/or taking sharp, unanticipated turns. But I could definitely be wrong.
I know that when I've stripped servo gears on a control surface of big r/c aircraft, the surface flutters rapidly and ceases to allow control in that axis. Similar flight through the air, but different hinge points (leading edge vs. mid-chord).
Genuinely interested in the results of the sub-scale flights!!!