aww, it looks so little

also looks sleepy with the eye lid

as for whether the eye lid should be seperate or not, i think people generally have eyelids attached to the mesh

probably because when you animate it, it will look smoother and more natural (how you would animate an eyelid is beyond me atm, but im guessing either smooth bind to a joint or bind to a lattice...)

but even if it was a still then you'd probably still have it as part of the head so it looks smooth when rendered