I think the mystery has been solved and Ueno Teruhisa held the winning lottery square. These look like Eucnetidae to me. Moreover, they act like Eucnetidae, leaping away when touched. These are the first eucnetids I've found, adding another beetle family to my personal list. This teneral specimen is still wearing part of its pupal skin. I placed three teneral adults in the container for the shoot so these images are of three individuals from the same larval/pupal batch.

We'll have to wait a bit to see what color they darken to. If testaceous (tan-orange), that should provide an ID in itself.