So I've downloaded a couple of watercolour brushes
Along with various watercolour textures to make a good background. If this works the characters and environment would have to be done in this manner.
These are the Backgrounds I've made for the art Direction style, I've also used it in my latest Profile picture (of which more are to come very soon)
These are the original photos I used so you can make your own textures form these as well which will definitely fit with how the chars are drawn/coloured.