I think I have something to offer you: Tomatoes are a sign of a court-boullion, or a 'couvillion'. https://www.deepsouthdish.com/2010/03/cajun-courtbouillon.ht...

Gumbo - as I was raised - doesn't include seafood. It's chicken and sausage. I do acknowledge 'seafood gumbo', and enjoy it heartily but when we teach it we teach the non-seafood gumbo first. I was told seafood in gumbo was a Northern influence, because we have other dishes like shrimp etoufee and jambalaya where seafood is well represented. I would say gumbo made with a roux is most common nowadays. I didn't know the file-based gumbo was probably how it originated based on seasonal availability. Sassafras grass, wow. :) I didn't know.