Want to point out that by word of the webmaster himself, Serebii, that those leaked types found on the japanese
Pokémon Sun and Moon site are highly likely
NOT related to the starters at all. According to him, the reason that this is debunked is because of the Ground type being in the wrong order, breaking down the whole theory supposedly. If they were actually true in any form, they would have been listed as
Grass, Flying, Fire, Ground, Water, Fighting, not
Grass, Flying, Ground, Fire, Water, Fighting.
As such, this also means that Rowlet is very unlikely to drop its Flying and go
Grass/Ground based on the types' order of this as people have been speculating for a while. That and
Grass/Ground doesn't even make sense for a Burrowing Owl, because these owls can still fly. Burrowing Owls are not land-locked. That said, coming to the debate of Litten, I'm still convinced and have faith that Litten is going to become either a
Fire/Rock or
Fire/Ground type, all of which is based on my own theory/speculation I posted several pages back, which in turn wasn't based on those typings found on the Japanese site. The latter was just by coincidence.
With these leaked typings being highly unlikely to be related to the Starters at all, I can only guess this means its open season again regarding speculation around the Starters of Sun and Moon. For me, I'm sticking with my theory and speculation regarding Litten.
For anyone who wants to read the exact quote made by Serebii on NeoGAF, here you go -
http://www.neogaf.com/forum/showthread.php?t=1216594&page=91