Mmm, if capsule shadows do not work on the GearVR, you could make a capsule the same height as the player character, add it to the character blueprint, in the same place as the character, and set it to not be visible to the owning player. This should give the same effect as using a head mesh. It’s not visible to the player, but it can still cast a shadow.
The problem with using the capsule is having it reflect, not sure how to get around this at the moment. It would be nice to have a light, shadow, and reflect option of “do not cast xyz on tag”
edit: Another way: Look at the showdown demo and see how Epic cast the “fake dynamic shadow” effect. I forget what technique they used.