Creole was the term given to the descendants of the settlers from France, Spain, Portugal, etc., usually people of at least some means (a lot of "second" sons of wealthy families). Creole food came about because the Old World ladies had trouble reproducing their recipes in the New World due to some things just not being available or available in quantity, and ended up having to rely on their slaves/domestics to help them adapt to what was readily available, as well as the "melting pot" effect of the different cultures. So, the original roots of Creole were actually Old World, with the addition/substitution of New World products and the African/Caribbean black influence.
The easiest way to differentiate between Cajun and Creole food is that Cajun is more country-style cooking and Creole is more city-style cooking. However, as time goes by, the 2 are merging more and more and becoming less distinct.
The original Cajun food included things that were readily available from trapping, fishing, hunting, etc. I'll guarantee you it was a Cajun that first tried crawfish. City folk would have eaten shrimp, oysters and fish long before eating something like crawfish. The Creole food is going to have the fancy sauces from France and will be more refined than Cajun, which basically is good home cooking.
We always make a roux as I'm not fond of okra or file. I've never seen a recipe in our Prudhomme, Wilson, or Emeril cookbooks that uses tomatoes, though after Googling I see that there are, though there seems to be a bit of controversy over whether tomatoes in any form, fresh, canned, or paste, belong in gumbo. Personally, I don't think I would want paste or canned in my gumbo. Maybe chopped fresh added in at the very last for freshness and color would be okay, but the others, just no, that doesn't sound good to me at all.
Some reference links if anybody is interested.
Louisiana's Food Traditions: An Insider's Guide
New Orleans Creole or Cajun? Here's how to tell
Experience Great Cajun & Creole Food and Recipes with Chef John Folse & Co.
Cajun vs. Creole - Escoffier