Since people are talking about sprites I'll jump in here.
I like the sprites, they're good, but there is a small problem I can see.
They don't really have a variation in color.
All 4 of the mons shown are almost entirely a single color of different shades
For example, the cover Legend is completely blue minus its beak and horns which is a bit underwhelming for a Pokemon of its position.
The starters are ok as they are, but maybe a bit more work with Caleaf as it's a whole lot of green in one space.
Assuming their evolved forms are more color diverse I think you'll be good