I really am trying to work through these challenge. I currently have a foot roll issue with toes not bending rotating the control bone (FootRoll.L) and applying action constraints on mechanical bones I have applied from to the ankle, ball and toes of the left foot. I have not worked on the right foot yet. Just trying to get the left one correct right now.
If I scroll through the frames in the action editor window, the foot rolls correctly from the ankle to the toes. But when I rotate using the foot control (FootRoll.L) the foot basically bends but the toes do not. File is attached under illustration called test.blend
Test.blend (1.6 MB)