Be careful when stirring your roux! (That's french for flour and oil/butter). It doesn't take much to splash it out of your skillet/slow cooker! I used oil instead of butter because cooking oil has a much higher smoke point that butter does and I tend to burn things (including myself) in the kitchen, but if you're feeling brave and you like butter better...have at it.
As for the cajun/creole seasoning, I used Slap Ya Mama seasoning because it is a big favorite of mine and Miss Add's. I used only a teaspoon and it flavored the whole pot. Miss Add thought it could use even more...the little rebel.
As for the seafood, use what you like. I love the larger shrimp. I think they give more flavor to the dish. I also poured all the juices from the crab and the crawfish into the pot to give it even more of a seafood flavor. Use whatever seafood you enjoy for this. After much research, I read folks using their favorite fish as well as oysters, clams and the like. You use what makes your mouth happy. As for me I'm gonna go make mine happy and have another bowl.
As with any of our recipes, calorie counts and nutritional information varies greatly depending on which products you choose to use when cooking this dish.
All slow cookers cook differently, so cooking times are always a basic guideline and should always be tested first in your own slow cooker and time adjusted as needed.