Sort the dried white beans to remove any small stones or debris. Rinse the beans, place them in a large bowl, and cover with several inches of cold water. Soak overnight, then drain and rinse before using.
Heat a large heavy pot over medium heat. Add the chopped bacon and cook until crisp, about 10 minutes. Use a slotted spoon to transfer the bacon to a paper towel-lined plate. Leave about 2 tablespoons (30 ml) of bacon fat in the pot.
Add the sliced smoked sausage to the pot. Cook until browned, about 5 minutes per side. Transfer the sausage to the plate with the bacon.
Add the chopped yellow onions, celery, green bell pepper, and jalapeño to the pot. Cook, stirring often, until the onions soften, about 8 minutes. Stir in the minced garlic and cook for 1 minute.
Return the bacon and sausage to the pot. Add the drained beans, chicken broth, ham hock, dried oregano, dried thyme, black pepper, and bay leaves.
Bring the mixture to a boil. Reduce the heat to low to maintain a gentle simmer. Cook uncovered for about 2 hours, stirring occasionally, until the beans are tender. If the liquid reduces too much, add a splash of water.
Remove the ham hock and bay leaves. Pull any usable meat off the ham hock, chop it, and return it to the pot. Discard the bone and fat. Ensure any pork whole cuts reach an internal temperature of 145°F (63°C) with a 3-minute rest.
Use the back of a wooden spoon to smash about 1/2 cup (120 ml) of beans against the side of the pot. Stir well to thicken the cooking liquid.
Taste the beans and add Cajun seasoning or salt as needed. Serve ladled over cooked white rice, garnished with fresh parsley and sliced green onions.