Sadly I think "yes" just because, well, its not wrong to begin with. They are familiar Pokemon returning with that part of the expansion. iirc the trailer also said "over 200 pokemon including the legendaries" (paraphrasing).Something I still havent got clarified is if the legendaryes / restricted coming back in Tundra are accounted in those 100+ or not for that expansion.
The optimistic me says no, but the realistic me says yes.
But despite the pessimism a part of me cant help but hope that maybe, just maybe, the 100+...is like 140+. If only so there's more than 50 new Pokemon to grab out of the standard Tundra without dealing with the co-op mode's legendary hunt.