On the japanese website, the icons for psychic, ghost, and steel are icon 07, 08, and 09

Ground and fighting's urls being 03 (between flying and fire) and 06 (between water and now psychic) respectively remain the same.

Further strongly suggesting Rowlet will be Grass/Ground, Litten will remain Fire, and Popplio will become Water/Fighting.
If the types' proximity to the starter types meant nothing, why wouldn't they make psychic icon 03 and ghost icon 06?

Ballio fucking confirmed get hype