Hey there! This is sort of complicated, but I will try to explain it as clearly as possible.
I have two different Spine files for the same character:
1 - Our default file with the diffuse images.
2 - A duplicate of the default file, but pointed to a different folder for normals. We're only using this file to pack the textures.
We're using multiple skins, so I have multiple image folders. We're pointing to one master image folder and then a few different folders inside of that for the various skins (pointing to these with the attachment path names).

The way the normals file works is that we have the exact same setup for the images, but the master folder is called images_normals (then inside of that, the skin folders have the same name). I did it this way so all we have to do is change the master image folder path and then we'd be able to pack the normals the exact same way as the diffuse images. We have all matching normal versions of the images so the atlases should match up in Unity.
So, first I'm exporting the diffuse/default file and it's packing all of our skins on the same atlas. That's working well. THEN when I try to export or pack textures from the normals file, it's ignoring duplicate images. I know this is happening because I changed a few things on the face PNG, repacked, and then it included both faces. It's happening elsewhere though, so I don't want to have to do that for all of the images it's leaving out of the atlas.
We DO need those duplicate images because we're using two different faces in the diffuse version, so we need two different faces in the normals atlas. I realize this isn't totally efficient, but it's only happening for a couple assets and we obviously need the atlases to match up.

Is there a way to:
a) pack the textures with ALL of the available images, even though some are duplicates?
b) a more efficient way to set all of this up?
Thank you!