Everstoned
Koffing and Weezing
I wouldn't really look at that as a hint either way. Personally I think we might get 5 differently colored Cores corresponding to the 5 hexagons in Zygarde Complete's chest.
I was thinking that too, but actually I think there's probably 6. At the beginning of either the act 4 special or the first episode of XY & Z (can't remember which XD), there was a zygarde underground in its 50% form. I think that core always stays underground in 50% form, and the other 5 cores roam Kalos. That way any one core can change to 50% form at a time, or they can all go into 10% forms to quickly run to the last core and merge into Complete Zygarde. Plus, you know, 6 cores, the hexagons, gen 6. It fits the theme nicely. Just my 99 cents of speculation though.