Probably, yes.
I'll describe what I do and what I want to achieve one more time for clarity:
I have a human character, in the setup mode it's posed in an 'idle' position. The character needs to move around a lot and to avoid a puppet look and have some keyposes look more like proper illustrations, I'd like to bind new pieces precisely to the bones and mesh and weigh some to be able to move the new pieces around a bit and not just swap to a still pose.
My art director in an early test used to scale a bone at a time in setup mode to bind textures. For example: if he needed a foreshortened arm, he'd scale the bone in setup, bind a shorter arm texture, then put the bone back to its basic position. This way when he'd need the forshortened arm, he'd scale the bone in animate mode and swap to the shorter texture.
After rigging some poses I thought I could bring this to the extreme and worked out a way to backup the position for all bones in setup, which is so:
I import the same project so I have a duplicate of the skeleton - and therefore a duplicate of the setup position.
Import the textures for the new position. I have exported them in place from photoshop and relative json.
In setup, move the skeleton to match the pose, even flipping and shortening bones if needed. Bind textures, weigh meshes etc as I would normally do. Now the new pose is ready and rigged. I usually backup this pose as well either by pasting the bone position in an animation in skeleton #2 or by importing another copy of the skeleton in the file (this way the new pose stays in setup)
At this point I copy the position of the bones of skeleton#2 from setup and paste them back to my main skeleton in setup. All is back to normal.
I recreate my new pose by pasting it from the backup, turn on the correct textures and I have it perfectly rigged with working weights and all
What it does that's unwanted is: sometimes I go back to setup or some animations and find some meshes are deformed. Most of the times if I still have my skeleton #2 in the file, I drag the mesh from there and replace it and all is fine
Before this I would import the new textures and align them to the skeleton in setup while the skeleton stays in its normal idle position. When I try to create the new pose in animate I need to move around the bones a lot and go back to setup to edit meshes and it's a lot of trial and error. Erika showed me how to use the preview to adjust texture but it's still a tricky process and you can't really weigh meshes in detail
Update: I tried rigging a pose without entering animate mode in the process. It looks like no mesh was deformed. Could it make sense or is it a coincidence?