You can adjust bone positions at runtime. One way to make this easier might be to create a one frame animation for each skeleton size with the bones moved on frame zero. This will allow you to see your different sized characters in Spine, though only in animate mode. To see the character in setup mode, you could select all bones in animate mode, copy, then paste in setup mode with the bones still selected. This way you can use the different sized bone positions to position attachments. When done, be sure to restore the setup pose to what it was originally, else you'll have ruined all your animations. Later, at runtime, use the appropriate animation to shift the bones. You wouldn't actually apply that animation, you'd just use it to modify the setup pose positions (BoneData). This will change the setup pose for all skeletons that use that SkeletonData, so you may need to load multiple SkeletonData instances.

You can scale the skeleton data when it is loaded at runtime, no need to export the data multiple times. You can pack texture atlases at different scales.

sketchi wrote

Aww they are so cute! I'd love to see how the final project comes out!

Nate wrote

To see the character in setup mode, you could select all bones in animate mode, copy, then paste in setup mode with the bones still selected.

This is so interesting and would have been awfully useful on an old project I had to work on two years ago. Instead of desperately trying to copy the animations from one skeleton to the other this would have been feasable.