My replacement bottom cover was delivered. I transferred all components and sent back the cracked bottom cover.
The guide for the bottom cover replacement doesn’t seem to be available yet (the URL on the inside of the bottom cover currently redirects to a 404 guide page). I just followed the guide for the mainboard and then removed the hinges. Was a simple process since all the components except the hinges have captive screws.
I noticed when taking out the mainboard that the cracks I had at the expansion slot corners are visible on the inside and extend directly toward the mainboard standoffs on both sides.
EDIT: After replacing the bottom cover without a guide I find ifixit already has a guide. But their guide currently doesn’t mention that you need to transfer over the speakers.