>>27470921I guess you can count Anistar because of the mention of the moondial, but the Strange Souvenir and everything from that Backpacker was clear evidence.
Regardless I think that somewhat early on they were obviously planning a Z version, which is why they designed Zygarde to begin with, and why they coded in Thousand Arrows and Thousand Waves, because those moves had no other reason to be in Gen 6 and don't even make sense to have another two signature moves to begin with. By early on, I'm talking pre-2013 here, and prior to XY's release they decided to scrap that and had enough time to work around it, and added in a few hints to SM. That's why they started ORAS exactly a year before it came out.