IK

There are only two IKs in this character's rig - one for each leg.
The IKs go from the ankle joint to the shoulder joint and uses an RP solver.

The pole vector of the RP solver is directed up when the toe is directed down.
Once we group the IK to a control (see next post), the pole vector is rotating with the group, so the knee is usually aligned correctly. The pole vector can be adjusted, but so far I never needed to do that.

The toes and fingers are not IK'd. I decided to set a control that simply rotates them with no IK. I also decided not to put a reverse foot mechanism. I hope that won't turn out to be a big mistake...