In a large pot, bring 6 cups of water, the crushed garlic, salt and pepper to a boil. Cut the pork belly into strips 1 inch wide, and about 4-5 inches long. Add the pork to the boiling water, reduce heat and simmer (covered) for 1 hour. After the first hour, add the chicken gizzards to the water and simmer for another 45-50 minutes. Drain and discard the water, then transfer the meat to a medium/hot grill. Cook the chicken for 1-2 minutes a side, and the pork for 3-4 minutes a side until they have a nice golden char. Cool the meat, then chop into "pea-sized" chunks. Set the meat aside until you are ready to prepare the sisig. Melt the butter in a cast iron skillet (preferred) over medium heat, then add the onions and ginger and cook until the onions just begin to brown. Add the chicken liver, and crush it into the pan with the blunt end of a spatula or a wooden spoon until it will mix easily with the other ingredients. Add the chopped meat to the skillet and cook for about 10 minutes, stirring about every minute or so. Stir in the chili sauce. Add in the garlic powder and soy sauce and stir for 1 minute to allow the flavors to blend. Stir in the mayonnaise, then crack the egg(s) right on top of the dish. Garnish with the scallions and lime wedges and serve immediately, making sure you get some egg with each serving.