(Tip) If you want to copy the body’s skin modifier to the head simply select the skin stack on the body and drag it onto the head.

If you want to copy the skin stack over to the head as an instance simply hold ‘CTL’ and drag it onto the head. The instance stack will appear in an italic slanted font.

This process works best when using envelopes for bones.

To finish off a set of eyes are added to the head and a LookAt constraint is added to their rotations to target a helper point.

Simply move the helper point to make the characters eyes look at the point of focus.