Very cool, Bonita

I wouldn't feel too tied to the shoulders in that first set if you don't really like them. They don't actually use the same artwork as the rest of the set at all! They actually come from a grey-blue version of the turtle scale artwork.
The reason is that no shoulder (or helm) art was ever created for that set, so the devs just borrowed some from a different set. Pick whatever you like knowing that there's no shoulders that were created for that set.
Actually, the same is true of all three sets you're using there... none of them have shoulders that belong to the same artwork as the rest of the set, none was ever created.