For what it is worth, many Cajuns mix their own combinations of spices for seafood boils, but the Zatarain's pre-mixed product is highly popular among the Cajun community. I get to see my Cajun cousins every so often when my wife visits her parents' graves in Chack Bay, about 5 miles outside of Thibadeaux, Louisiana. Sometimes we talk about food in a serious way, comparing recipes and such. My wife's jambalaya and gumbo are both really good. She prefers the chicken-and-sausage gumbo to the shrimp-and-crab gumbo, not to mention that the cost of crab meat is through the roof at the moment.
I found a reference to that "making a pond" series online but so far can't tell where they are except by implication. I'm sure they reference it, but I'm not going to listen to a dozen-and-a-half rambling videos to listen for auditory clues. As flat as that land appears to be, they are in southern Alabama, probably not that far from Mobile. The Cajun influence of crawfish boils doesn't reach that far north from the Gulf Coast because once you get as far north as Montgomery (the state capitol), their food becomes incredibly bland.
I dearly love my Alabama cousins - but their cuisine is incredibly bland. If it weren't for the freshness of their home-grown vegetables, I would do just as well with old frozen veggies, flavor-wise. And let's not talk about their coffee.