I think the title was bedtime stories or goodnight stories, something like that.
The cover was a scene with trees and leaves, might have been autumn. In the foreground is a witch and a fox in a raincoat (maybe?) and they are surrounded by iridescent bubbles.
The book was a few short stories about animal characters:
In the first, a young fox (his name might have been Freddy)’s mother makes him a new raincoat and sends him off to play with friends, warning him not to get his tail wet. The friends end up sailing down a stream in an upturned umbrella and the fox’s tail hangs out and gets soaked.
In another one, two other animal characters sneak into a local witch’s house and mess around with some spells, turning the sky green and grass blue.
Another one had all the animal children go to the beach with school. The fox character meets a mermaid who gives him a shell to remember the sound of the sea.