Begin by slicing the chicken breast into thin strips.
Cut the bell pepper and cabbage into chunks, and dice the onion. Set aside.
Add stir-fry oil to the wok and heat medium-high for 3-5 minutes. Then, add the chopped bacon. Cook until barely turning brown.
While the bacon is cooking, whisk together the chicken mei fun sauce ingredients in a medium-sized mixing bowl. Set aside.
Add sliced chicken and stir with bacon, making sure it's coated in oil. Cook until the chicken is no longer pink, then add shrimp. Continue cooking until the shrimp is done (completely pink). Transfer the mixture to a separate bowl and cover it with foil.
Add the rest of the stir-fry oil to the wok. Add the mixed vegetables (minus the cabbage) to the wok, incorporating them into the oil. Let them cook down until softened and fragrant. Then, add the cabbage and stir to combine.
Cover the wok with a lid and allow the vegetables to steam until the cabbage is slightly softened—about 5 minutes. Once done, transfer to a separate bowl, uncovered
Pour chicken mei fun sauce into the wok and heat until it bubbles around the edges, but do not bring it to a full boil. Then, begin to fold in the rice vermicelli noodles in batches, tossing to fully coat before adding more.
Add the chicken, shrimp, and bacon mixture to the noodles, gently tossing with chopsticks, tongs, or a wooden spatula.
Add the vegetable mixture and gently toss it with chopsticks, tongs, or a wooden spatula.