In a bowl, combine pork and ½ cup of the vinegar. Season with salt and pepper to taste. Marinate for about 30 minutes.
In another bowl, combine liver and the remaining ½ cup vinegar. Season with salt and pepper to taste. Marinate for about 10 minutes.
Drain pork and liver separately and reserve marinade. With hands, squeeze to extract excess liquid.
In a pan over medium heat, heat oil. Add onions and garlic and cook until softened.
Add pork and cook, stirring occasionally, until lightly browned.
Add fish sauce and cook for about 1 to 2 minutes.
Add the reserved vinegar marinade and bring to a boil, uncovered and without stirring, for about 3 to 5 minutes.
Add water and bay leaves and bring to a boil, skimming scum that floats on top.
Lower heat, cover, and continue to cook for about 25 to 30 minutes or until pork is tender.
Add labanos and cook until half-done.
Add liver, stirring gently to combine, and continue to cook for about 5 minutes or until liver is cooked through, labanos are tender yet crisp, and liquid is reduced.
Season with salt and pepper to taste. Serve hot.