Cook noodles according to package directions. Rinse well with cold water then set aside. This will prevent the noodles from being soggy and overcooked.
In a wok or large pan over medium heat, sauté garlic and onions. Add liver. Cook for 5 minutes then add carrots. Lower the heat then cover with lid. After 5 minutes, add sweet snap peas and cabbage. Season with a teaspoon of oyster sauce, soy sauce and fish sauce. Continue stirring until vegetables have softened but not overcooked. Remove from pan then set aside.
Pour pork broth in the pan. Add remaining oyster sauce, soy sauce and fish sauce. Bring to boil.
Add noodles and half of the sautéd vegetables and liver. Gently toss together. Remove pan from the heat after 1 to 2 minutes. Season with pepper and a little salt. You don't need to much because the sauce will add more saltiness later.
Transfer to a serving plate. Garnish with pork, quail eggs, remaining vegetables and green onions.
Meanwhile for the sauce: mix 2 tablespoons vinegar, 2 teaspoons calamansi juice and onions. Add soy sauce one teaspoon at a time. Try it, taste it then adjust accordingly.
Serve on individual plates and pour the sauce on top.