Place pig trotters and chicken backs in a pot on stove of boiling water, reduce temperature to simmer. Simmer for a minimum of 10 minutes, skimming off foam as it cooks. Remove trotters and backs, set aside, discard liquid. Pick out any dark or bloody bits from trotters and backs.
Place trotters, backs, leeks, shallots, ginger, mushrooms, and pot belly in instant pot. Close pot and cook on "soup/broth" setting for 2.5 hours.
Place soy sauce, mirin and 4 Tbsps water in ziplock bag, place eggs in bag, and place in refrigerator, turn occasionally (can be done night before).
After 2.5 hours, release pressure and open. Remove belly, wrap tightly in cling film wrap and place in refrigerator. Close Instant Pot back up, set for another 60 minutes on "soup/broth" setting.
Once done, release pressure, then strain broth and throw out solids.
In separate pot on stove, boil water. Using a small mesh strainer, cook ramen in water until done, remove and strain, and place in bowls. Using same mesh strainer, cook bok choy leaves in same pot of boiling water for 30-60 seconds, strain.
Take pork belly from refrigerator, remove cling film and slice thinly. Arrange pork belly, bok choy, corn and green onions in bowl over ramen noodles. Ladle hot broth over other ingredients, top with halved eggs and serve.