I actually didn't like the Super Bowl Pokemon video: This is just another Kanto-marketing spam video, and it only shows Zygarde because they have to sell the game! They need to show all gen Pokemon, not just gen one!
“To celebrate 10 years of Pokémon GO and 30 years of Pokémon, we're excited to introduce "What's Your Favorite?", a new photo feature now available in Pokémon GO.”
This is the official art for this feature. No bug, no grass and no ice Pokémon representation whatsoever.
Which criteria do you think was used for those Pokémon that do appear?