Fried Oyster Po-Boy with Remoulade Sauce

For the remoulade sauce
1 1/2 cups mayonnaise
1/3 cup sour cream
1/4 cup Creole mustard
3 tablespoons thinly sliced green onions
1 tablespoon paprika
2 teaspoons Cajun seasoning or Old Bay
2 teaspoons prepared horseradish
1 teaspoon garlic powder
1 teaspoon Crystal hot sauce
1 teaspoon sweet pickle relish
For the oysters
1 cup self-rising cornmeal mix
1 cup all-purpose flour
1 tablespoon Cajun seasoning or Old Bay
Kosher salt and fresh-ground pepper, to taste
2 to 3 quarts canola or vegetable oil, for frying
40 fresh-shucked or jarred oysters, in liquid
For serving
French bread
Shredded lettuce
Bread & Butter pickles
Sliced tomatoes
Red onions, halved and sliced into half-moons
