Heat oil in a large heavy bottom pan. Add in onions, celery and 1/2 of the bell peppers plus the garlic. Saute over high heat until translucent and add in the butter
Slice the sausage into rounds and add to the vegetables along with the chicken cubes. Cook evenly on all sides, be sure to get some brown color into the proteins.
Add in the okra and allow to cook for about a minute, stirring occasionally.
Add the stock, seasonings, chilis, and tomato sauce. Bring to a boil.
Turn back the heat to a simmer. Allow to simmer for about 10 minutes. Then add in the tomatoes and the rest of the peppers. Cook for 2 more minutes. If you are adding zucchini, saute it in a little oil and season. Then add in at this point.
Check the flavor and consistency. Add salt and pepper. If it seems a little thin, bring to a boil and whisk in a little cornstarch mixed with cold water.
Make the white rice by boiling water with a cinnamon stick, salt and pepper. Add in the rice and bring to a boil. Cut back to a simmer and cook until all the liquid has been evaporated. Add in a little olive oil or rice and stir in.
Serve the gumbo in a bowl with rice on the side.