So far I have received my new social security card with my new last name so it’s technically changed, but it’s going to take some time to finish updating my ID, passport and bank accounts.
I’m not sure what the best route is in which name to use to ensure Amazon approves my account.
You should use your new last name when setting up your Amazon Seller Central account, even if you have not yet updated all of your other identification. You can provide Amazon with a copy of your new social security card as proof of your identity.