So this isn't really a leak what i'm presenting to you but something I think you'd all find interesting as big as bullshit as it sounds i've been associated with GF in some way in the past. Some of the new pokemon shown for this generation already were actually planned to be included in XY however due to time constraints were pushed to Sun/Moon. Out of the ones revealed thus far, the list goes as follows:

>Cutiefly
>Stufful/Bewear
>Mimikyu
>Bounsweet
>Mudbray/Mudsdale
>Fomantis/Lurantis

because of this i'm guessing they plan to at least have a decent size pokedex as compared to last gen, but who knows.