You got yourself a simple lil prob to fix. Your head attributes are greyed cause they are locked. Just highlight them (the locked attributes) in the small lister(not the full sized attribute editor) and rightclick, click unlock and they will turn white again. Then you can do a Edit>Duplicate>Option Box. In the option box you will see a checkbox for duplicate input connections/input graph. UNcheck that so that you get just the mesh instead of the mesh and all its history.

If you have your head bound using a rigid bind you can Skin>Edit Rigid Skin>Preserve Skin Groups>Detach Skin (with the head and any joint selected). It will detach the head, you can do with it was you will (except add/subtract verts) then Skin>Edit Rigid Skin>Preserve Skin Groups>Reattach Skeleton to put it back on.

Once you get it duplicated you can edit the mesh as you need for making the blendshapes. When you are done with that select all the target shapes then the original mesh and then Demorfers>Blendshapes>opion Box. MAKE SURE THE ORIGIN IS SET TO LOCAL!!!!! or you head will float back to the origin space afer you start animating(i just found that out the hard way).

Hope this helps.