However, with the alien's foot, I had far more joints that I would need to control using the reverse controller.
I found that this was going to be problematic when trying to rotate the foot on the toe as it would only effect the inner toe. So because of this I decided to reparent the middle and outer toe RL joints to the foot RL joints. In order to make the foot and reverse control match, I decided to reparent the outer toe on the foot to the foot joint.
The next part was to create an IK handle for the leg that ran from the hip to the ankle, and also to create IK Handles for each of the joints in the foot, which would then be parented to the corresponding joints in the Reverse Control. Here is a video of me parenting the newly created IK handles to the reverse control and also creating a few new ones in order to make the foot move more evenly.