That's interesting. Seems like we might be able to expect some news sometime tomorrow, then.
In the meantime, here's my idea as to how Zygarde's various formes will be handled in-game. Basically, my thinking is that you get Zygarde Core very early on in the game. Very weak, low BST, on par with early-game stuff like Pidgey and Rattata. Later on in the game, you acquire a Key Item designed to store Zygarde Cells, so that Zygarde Core can use any number of them to piece together one of Zygarde's formes. Let's call this the Z Container. The Z Container would come with 10% of all the Zygarde Cells already inside, allowing you to use the Z Container to switch Zygarde between its Cell and 10% formes. As the storyline progresses, you gain more and more Zygarde Cells, and viewing the description of the Z Container in the bag tells you what percent of all Zygarde Cells are in the Z Container. Once it hits 50%, which would be at some point around the middle of the storyline, you can use the Z Container to scroll through Cell, 10%, and 50% formes- use it on Zygarde Cell, it becomes Zygarde 10%. Use it on Zygarde 10%, it becomes Zygarde 50%. Use it on Zygarde 50%, it's back to Zygarde Cell. Like a Deoxys meteorite in Key Item form. Once it gets 50% of the Zygarde Cells ,the number stops going up. And then, when the storyline reaches its climax, your Zygarde appears (if it's in the PC, you get the option to add it to your party following this cutscene), and summons the rest of the Zygarde Cells from all over the world into the Z Container, and then becomes Zygarde Complete Forme then and there. And from then on, Zygarde Complete is added to the rotation of Zygarde's formes you can use the Z Container to scroll through.
