I know a bit about Studio Ghibli-rather than watercolour they use a gouache type paint for their backgrounds-Nickers poster colour. Cheap in Japan but expensive to import to Australia. The greens are very characteristic and layered-somewhere on YouTube I found a demonstration of how they were done
Itís very fluid use of semi-opaque paint with linework low contrast done with a brush rather than paint. Gouache paint used thinly could give some of the same effects. The other artists I donít know and they look more conventional watercolour and ink, but again with the ink being brush rather than pen and lower contrast than black Indian ink and more fluid in line than can be done with a multiliner or similar fineliner. All the Japanese animation artists seem to masters of aerial perspective.
Your pictures seem to be heading in the right direction, especially the toadstools, but compared to the Japanese work, they have higher contrast between line and colour, different colour palette, and are flatter- they donít use aerial perspective in as sophisticated manner. Miles better than anything I could do!