Heat 1 tablespoon of oil in a large skillet over medium-high heat. Add the sliced sausage and cook until browned on both sides, about 5-7 minutes. Remove with a slotted spoon and set aside.
In a large, heavy-bottomed Dutch oven or stockpot, combine 1 cup of flour and 1 cup of oil over medium-low heat. Cook, stirring constantly with a flat-edged wooden spoon or spatula, until the roux turns a deep, chocolate-brown color. This will take 45 to 60 minutes. Be patient and do not let it burn.
Add the diced onion, bell pepper, and celery (the 'trinity') to the hot roux. Cook, stirring frequently, until the vegetables soften, about 8-10 minutes. The roux will seize up and become pasty.
Stir in the minced garlic, Creole seasoning, and dried thyme, and cook for one minute until fragrant.
Gradually pour in the warm chicken stock, about one cup at a time, whisking constantly to incorporate it smoothly into the roux mixture. Once all the stock is added, bring the liquid to a low boil.
Add the bay leaves, the reserved browned sausage, and the shredded chicken to the pot. Reduce the heat to a low simmer. Cook uncovered for 45 minutes, stirring occasionally.
Stir in the sliced okra. Continue to simmer uncovered for another 30-45 minutes, or until the gumbo has thickened and the flavors have melded. The chicken should be tender. Ensure the gumbo reaches an internal temperature of 165°F (74°C).
Remove the bay leaves. Skim any excess oil from the surface. Taste and adjust seasoning with salt, pepper, and more Creole seasoning if needed.
Serve hot in bowls over a scoop of white rice, garnished with sliced green onions and a dash of hot sauce.