Kaiyodo seems to alternate. The soil invert set for example has some in hard plastic/resin and some in soft flexible plastic, and I believe a few have some parts of each. Whereas the bird garden set seems to have used a plastic more in between, something equivalent to the Favorite soft models or Safari ltd. etcetera.
Though most still have some assembly, the Capsule-Q Museum figures definitely aren't as "puzzle-y" as the older Dinotales and Choco-Q.