Probably posted a bunch, but just in case, seeing overworld Pokemon and random battles are in the non Wild Area parts.
Yep and they detail this on the description on the main Website
The Pokemon encounter system is a massive mix of ideas in ALL Areas of the game
In tall grass or caves, wild Pokémon can jump out at you. Battles with wild Pokémon will occur when you run into Pokémon that you can see wandering around. Some Pokémon will pursue you once they see you, while others will run away.
Also, the ! mark that will appear above tall grass also seems to be an indicator of wild Pokémon hiding there!
