For the brine and turkey: Pour the hot water in a large and deep non-reactive pan, bucket or large cooler with ice. Stir in the molasses, salt and brown sugar until fully dissolved. Then add the peppercorns, lemons, onions, garlic and rosemary. Add the cold water and let cool to room temperature (or put in the refrigerator). Place the turkey in the brine. Using a syringe, inject the turkey with some of the brine. Cover and leave in the brine for 48 hours in the refrigerator.
For the stuffing: In a skillet over high heat, cook the bacon until almost crispy, about 5 minutes. Add the celery, garlic, leeks and onions. Continue cooking until translucent. Add the ground turkey and cook until browned. Add the paprika and cayenne. Season with salt and pepper and let cool. Meanwhile, soak the bread in the milk in a small bowl. In a large bowl, combine the soaked breadcrumbs, the bacon mixture, cheese, chives, dill, parsley and green onions. Season with salt and pepper. Set aside part of the stuffing to stuff the turkey. Form the remaining stuffing into meatballs using a 1 tablespoon measurement. Reserve on a baking sheet covered with parchment paper. Cover with plastic wrap and keep in the refrigerator until ready to cook. With the rack in the lowest position, preheat the oven to 325 degrees F (170 degrees C). Remove the turkey from the brine and dry thoroughly.
To roast the turkey: In a bowl, mix together the butter and garlic. Set aside. Fill the turkey cavity with the reserved stuffing. Tie the drumsticks together with kitchen string to help the turkey keep its shape. Rub the turkey in between the skin and the flesh with the garlic butter. Sprinkle with salt and pepper. Scatter the leeks on the bottom of a large roasting pan and pour in the chicken broth. Place the turkey on the leeks. Add the meatballs to the pan. Roast for about 5 1/2 hours, basting the turkey with the broth every 20 minutes, until a meat thermometer inserted in the thigh without touching the bone reads 180 degrees F (82 degrees C). If necessary, add more broth so there is always about 4 cups/1 l liquid in the bottom of the roasting pan. If any parts of the turkey begin to scorch during cooking, cover them with aluminum foil. Place the turkey and meatballs on a serving platter. Cover and let rest 20 minutes. Strain the liquid from the roasting pan into a saucepan and skim the fat at the surface. Adjust the seasoning. Reduce the sauce to the desired consistency. Keep warm. Serve the turkey with the roasting sauce and the turkey meatballs.