Easy way to add multi-layered support is just to save multiple images, to layer them and to delete what you don’t need, leaving the extra parts (boots/feets in this case) as transparent, and there you are. 🙂
You can edit all season 2 male packs at the same time, or all season 2 female packs or all season 2 muscular packs. Season 1 packs are autonomous (but you can mix the resulting pics externally of course).
Just select everything you intend to use while launching the soft.