I understand that the middle bar in that S-AWC HUD display is the ACD output, but what about the two semi-circle bars beside it? Is it the AYC?

Yes, it is just telling you how hard it's working in either direction. If you are making a right turn at very fast speeds the left side lights go up depending on how much the AYC is spinning the left wheel and the right side lights down depending on how much it's braking the right wheel.

That's going to be fun to watch.