Consider adding Soul Soil to one of the beginning Pokemon:

Burmy
Pineco
Phantump
Drifloon
Shedinja
Nincada

This is because Soul Sand is the first building material the player is given, it's mostly inert and safe for building, and it lets one expand a 'outdoors' habitat.

Soul Soil drops have been added infrequently to Drifloon and Burmy, and guarenteed to Nincada, giving Nincada a purpose in the early game ecosystem in that they help you build habitats.

Will be pushed in 1.1.3