Here is the image I created with shape layers in After Effects. A bit tricky getting used to the tools! I plan on adding fireworks out of shape layers once I get to animation.
I ended up making some slight adjustments to the scene's colors, art, and object placement before and during the animation process. I had a lot of fun making the fireworks out of shape layers and am pretty proud of how they turned out. I edited the gif version to not have a fading sky since it blew out my 256 color palette. Vimeo is embedded under the gif with the sky transition.