The Zygarde news seems very intriguing.
First up is the flat green blob being called to as the Zygarde Cell - it has a seemingly empty space in it's stomach and vacant pupils.
Then you have the non-flat blob called the Zygarde Core, which is the brain of every form. Judging by the difference between the Cell and Core I think the Zygarde Core actually specifically refers to the red stone thing that occupies the previously empty space.
Ie The red stone is the Zygarde Core and the blob is the Zygarde Cell - adding the Zygarde Core to the Zygarde cell makes it become more sentient (pupils go from green to black) and generally more active/alive (it stands up and rounds out more)
The Zygarde Dog is refered to the Zygarde 10% Forme
Normal Zygarde is refered to as 50% Forme
The big mecha thing is Zygarde Perfect Forme
Kinda suggests imo there may be up to 11 formes in all based on percentage progression - 0% Cell, 10% Dog 20%? 30%? 40%? 50% Normal 60%? 70%? 80%? 90%? 100% Perfect
Either that a 6 Forme setup (0,10,25,50,75,100)
Also yeah with it being XY & Z Anime pretty much confirms we are back to the mid-gen sequel being a third variant instead of 2 like they did for gen 5 and deffo looks like a mega Greninja, which almost certainly indicates Z will see a bunch of new megas and that Delphox and Chesnaught will be going mega too. Unless they pull another Blaziken and Greninja is a promo with his counter parts following in the next games, presumably Gen 7 since Z would round out the expected main series titles for gen 6.
Also side bar - on my quest to complete as much of a livingdex with hidden abilities as I can and looking to to start doing a shinydex follow up is that Jirachi is a weird case. It was 100% legit possible to get shiny Jirachi in earlier games but you can't get it through pokebank fake checks making it the one case of a pokemon that can legit be shiny becoming impossible to be legit shiny.
All the other not possible as legit shiny have just never been released as a shiny, either due to being event only like celebi, meloetta, keldeo, diance and hoopa or being shiny-locked in every wild encounter to do like Xerneas, Yvetal and Zygarde