Pretty neat setup. The human foot has a lot more flexibility than people think. Once you start rigging you think, oh, and it has to do that...and also do that...and...
I've seen some pretty complicated leg/foot rigs done in other apps, but this looks pretty simple to get good results.
Thanks. Since feet are the base for a stance. And a stance conveys so much
in the way of intent, it can be even more important than the facial expression.
Here's a new torso rig, with the offset foot thingy, and more.
I used Cheetah's layers to color code:
Green = Control, Pole or Target (Move, Pose and Keyframe with these)
Blue = Free Bones (Move directly)
Red = Bones influenced by an IK Tag (Can't be moved directly, move with control, pole or target)