So looking through the database and I managed to catch a few duplicates based in the USA:
-Harry Smith/Davey Boy Smith Jr (Harry Smith has the alter egos)
-Slyck Wagner Brown/Slyk Wagner Brown (Not sure which one is the duplicate)
-Konnor/Ryan O'Reilly (Konnor has the alter egos)
-Curtis Axel/Joe Hennig (Joe Hennig has the alter ego but not as Curtis Axel)
-Jayson Paul/JTG (Jason Paul has the alter egos)
-Melina/Melina Perez (Neither of them have alter egos but if I had to guess Melina is the duplicate)
-Tenille/Tenille Dashwood (Tenille has the alter egos)
Hope that's narrowed down the duplicates, atleast in the USA anyway, not sure about duplicates in the rest of the world but regardless looking forward to getting into the mod