I vaguely recall that for some reason vantablack is toxic. So the new stuff is a better idea anyway.

The scleral lenses are probably still out, but the facemask looks a lot more doable.

Aluminum (not foil, but very thin) with lots of tiny holes thru it. do the chlorine and vapor deposition, and voila!

A black void under a hood would be adequately scary. But the void instead of eyes would still be best.