Very interesting series, especially for a Prius owner like me!
I must confess that the Traction-Dontrol and Stability-Control implementations on the Prius are one of the few things I don't like about the car.
You pointed out that it uses individual-wheel-speed information and controls braking of individual wheels to perform these functions. That is what I would expect it to do, but I wonder if it really does.
One maneuver that my 2009 Prius does especially badly, is a sharp right turn merging into traffic. The right front wheel in that scenario has a strong tendency to slip, as we'd expect. I would expect the TC/ESC system to apply the brakes to that wheel to stop it slipping. Instead, what it seems to do is shut off all power to all of the wheels! The car I'm trying to merge in front of could easily hit me.