>>30431125I think people have the Nihilego = Lillie thing backwards. I think Lusamine dressed Lillie to look like Nihilego on purpose, in her obsession. Hence why Lillie finally changes clothes (clothes she purchased earlier but never had the courage to wear) just after the first confrontation with Lusamine, symbolically taking charge.
I like the idea that there's a correlation between the UBs and the main characters, but I have throuble seeing some of them, like Celesteela and Buzzwole.