There was a talk about the #666 pokémon a few posts back, so whatever: #666 will be a Houndoom evo. #658 is Froakie's last evo, #659-660 are the early rodent, #661-662 is the early bird, #663-665 is the early bug. Houndoom evo comes eight slots after Watermon's final stage; before that, Crobat was the earliest old-gen evolution to appear in a generation (#169, nine slots after Feraligatr). Perfectly plausible, and means we would be getting an early option for a Fire-type for the heretic who don't choose Fennekin. There will be 128 new pokémon. The last one, an event legendary, will be #777, with Super Luck or Serene Grace and a whole movepool full of shit to abuse their ability. Also, Tri Attack and Metronome, obviously.