I noticed that the Kalos starters are all weak to the Alolan starters (assuming Luchalitten is Fire/Dark). Flying beats Fighting, Dark beats Psychic and Fairy beats Dark. I think they are definitely related in a way. Kalos won't appear in SM but Zygarde will, so there will be Kalos-related stuff in it without a doubt.

It's been also rumored that these two batch of starters will get a form change when they use a Z-move. The second leak (Morelull, Salandit, Pykumuku AKA the real Chinese leak) confirms Z-power activated form changes.

I think that will be what is in the anime known as synchro or bond phenomenon. They starters will take after their trainers. Whether Artleaka's drawings are real or fake he showcased how a "bond" or "synchro" could work in game.

Rockruff's evo will probably be capable of this (and who knows what else too) but that's irrelevant now.