couldn't tell you about blend shapes but I can give you a very simple way to do that now do you have the eye lids created yet? Split the eyelid into two pieces and rotate them so they are mostly hidden behind the head. For a Basic concept
Create------->Nurbs Primitives-------->Sphere
Imputs------>End Sweep--------->90
Rotate------>Z 90
Edit-----------> Duplicate
Rotate-------->Y 120
Duplicated Sphere
Rotate--------->Y 90
That will kind of give you my overall perspective for a blinking movement hope this helps