@kylebeaudette Ahhh!!! I can't love this thread enough. Your witch is SO endearing, I love her!! I love this style so much, I think nostalgia plays a big part in why it's so easy to connect with as well. Please feel free to post, post, post!
I feel watercolour definitely fits this style best in my opinion (you could also try markers?). Digital can quickly feel flat if you don't build up your textures and overuse the airbrush (that always makes my images look too digital).
I'm sure there must be a way to imitate watercolours successfully with digital, but it's not easy. Lucy Fleming recently did a blog post on digital watercolour which you might find interesting ^_^ She has a lot of great brushes for Procreate.