Does anyone know of a lightweight motorcycle style open face helmet for eBiking?
Track racing helmets have a built in visor, but these usually only cover the eyes. 

You can probably achieve what you want with a combination of a non vented helmet, wrap around glasses or goggles and a half-face mask or balaclava.

There are numerous bicycle specific helmets made for commuting or casual riding that have minimal vents, or closable vents. Some have cold weather liners that fit to the chinstrap to cover the ears.

There are half-face masks made for skiing, cycling or other cold wether use that are semi-rigid so that there is space between the mouth and nose and the mask.