To make a facial rig, with movings eyes, mouth and eyebrows, you'll need to edit a skin, and remove the eyes and area of the mouth on a skin with an external image editor.
When you import your skin, it'll have 'holes' where they are.
You'll need to use the parenting feature of mineimator to create resources and fill the gaps, creating moveable pieces.
I'd help you, but there are a million ways to create such a rig.
The only way I can suggest to do so, is to download someone else face rig and have a look, and see how its done.