Ouch, this wasn't the expected answer. I assumed lots of people updated existing PSDs and added more and more images over time and would want to export json additive import the new images into the spine project.
We're on 3+ so not sure if you meant there's a way to do it or only if we were on Spine < 3 there might be an option.
The final pos and rotation part is exactly what I'm trying to avoid specifically 😉 All our images are quite different per armor set, so the only thing I've found is to import a new skeleton to the project and then drop the opacity to 10 and just copy paste their rot/pos. Was just hoping there was a much better flow.
I think it's still important we re-do the entire character with the pose the same as the PSD so that we don't have completely unknown staging for the images going forward. Unless you can suggest a better way... importing new armor sets is a complete guess as to what their pos/rot should be if you move your base pose from PSD.