>new prof is a returning character
>some speculate it is Clemont
Personally I think it'd be the unselected rival Calem/Serena or even one of the other three rivals or even Korrina since Sycamore's research field is Mega Evolution but if it truly is Clemont, does that mean we'll get an older Bonnie or something?

That does beg the question of how the Ashnime- well I guess it's the Likonime now- will deal with this, which is part of my doubt that it is Clemont. I mean, same reason why Cilan wasn't of the Shadow Triad right?