This week I worked on completeing those sky planes in After Effects. I have a day time, a night time, and an evening/dusk. I used a multitude of animation layers and painted parts of it as well.
Here are those examples:
Each of these came out pretty well in my opinion, it isn't too realistic and not too stylized. I am still iterating on the evening sky, but that is not a priority currently. We are working on finishing another scene to full render and I have been working on UVs and textures with Aelma.