Even though the tail on the left Pokemon does look somewhat like a leaf, I have a good feeling that it's actually some sort of fire. The one on the top looks like it has a two leaves on it's head but I'd be pretty disappointed if that happens considering Turtwig had leaves on his heads too. They could just be ears though. The one on the right is likely water because it looks like he has a beaver tail and webbed feet. Meh, I'll probably be wrong when the actual Pokemon are revealed but that's just what I think from the silhouettes.
Yeah, that's pretty much what I was thinking. I'm hoping the one on the left is the grass starter, because if not that means it'll have flames on its tail and I don't want a Chamander copycat.
EDIT: Or we could all be completely wrong and they'll break the mold and change the starter types. Or not, since that's what everyone was saying about the last generation of starters and it ended up being grass/water/fire.