I just want to make clear lest anyone reading this thread comes away with the wrong idea.....
Whether or not a derailleur is “Shadow” is completely irrelevant in terms of compatibility.
If you logic model or decision flow chart for determining compatibility involves “Shadow”, then it is flawed and you need to start over.
Here is a good article from BikeRadar regarding mixing and matching. Nowhere is Shadow mentioned as being relevant:
https://www.bikeradar.com/advice/buy...r-derailleurs/