Cover beans with cold water and soak overnight.
Drain beans and place in a large saucepan with onion, carrot, bacon, bay leaves, ham bone, and garlic.
Cover with water, boil, skim the surface, and simmer for one hour until beans are almost tender.
Melt duck fat in a second lidded saucepan over moderately high heat.
Fry cubed pork until golden and set aside.
Fry bacon lardons until golden and add to the pork.
Halve the sausages and brown them in the same fat.
Fry sliced chicken and corned beef sequentially and set aside.
Soften sliced onions in the fat, then add garlic, tomatoes, and bay leaves.
Return meats to the pan, cover with water, boil, and simmer covered for 45 minutes.
Preheat the oven to 160°C.
Drain the beans, reserving the liquor and bacon, discarded the carrot and onion.
Cut pork and bacon into strips and place meat in a casserole dish topped with some beans.
Layer remaining meat, onions, beans, and duck confit, then add meat liquid and bean liquor.
Top with half the breadcrumbs and bake for one hour.
Stir in the crust, add remaining crumbs, drizzle with liquor and fat, and bake for 30 minutes until golden.