Has it been confirmed if the one you choose affects wether or not you can get Mega stones for the other 2?
I want to use Squirtle for my in-game team along with Fennekin (and boxing Torchic b/c I already have a good Blaziken in White) I really want to make sure I can get Mega Charizard though since I got a good Solar Power Charizard waiting in White along with the rest of a Sun Team.
If the choice affects the Mega stone I'll feel forced to go Charmander. If not then I could go with Squirtle freely.
And no I wont switch out Fennekin, choosing the Fire type on my first playthrough has been a tradition in all my games.
We don't know yet. But I'd say there's a good chance the Kanto starter you get will be holding Venusaurite/Charizardite/Blastoisite and that'll be how you get it. Or maybe not and they will have a way to let you get all three. --- "The difference between fiction and reality is that fiction has to make sense." -Tom Clancy
My best guess is that whichever Kanto starter you choose will be holding its Mega Stone. There might be a chance that they all share a Mega Stone- maybe Kantonite?- in which you'd be fine. --- Folkmiza everywhere else.