Although I still suspect that I’m misunderstanding something here, I’ll try to be helpful:
Renaming the filename seems to work alright, although, maybe a macro button to automatically rename the files would streamline the process for some.
When I upload any images to anywhere other than Holopix, the image is naturally presented as two frames, if you like, for left and right, within the one image.
(As it does when I open the image within photoshop.).
To extract the two images, surely it’s a simple crop and save for each side.
I understand that you’re using Leia Player, however, during the development, Leia prioritised features which other (accessible) software didn’t do.
As a result, everything you can do with snapseed, for example, was not prioritied as features for the Leia Player.