Heat oil in a medium skillet over medium-high. Cook shallot, garlic, and chile, stirring often, until shallot is softened and translucent, about 4 minutes. Add pork and cook, stirring occasionally, until almost cooked through, about 3 minutes. Add fish sauce, soy sauce, and sugar and cook, stirring occasionally, until moisture in skillet is evaporated, about 5 minutes. Add broth, reduce heat, and simmer, uncovered, stirring occasionally, until liquid is evaporated, 12–18 minutes.
Remove skillet from heat and mix vinegar into pork mixture; taste and season with salt if needed.
Slice tofu 1/2- inch thick. Place on rimmed baking sheet between layers of paper towels; sandwich with second sheet and place cast iron skillet on top to weigh down 10 minutes. Cut into cubes, transfer to bowl and toss with cornstarch.
Meanwhile, cook noodles per package directions and rinse with cold water; drain.
In small bowl, combine soy sauce, sugar, chili sauce, lime juice and garlic; set aside.
Heat 1 tablespoon oil in large nonstick skillet on medium. Add pepper and cook until tender, 4 to 5 minutes. Remove from skillet. Add tofu and cook, tossing, until golden brown, 4 to 5 minutes. Add noodles and sauce and toss to combine. Fold in pepper, sprouts and scallions and cook 2 minutes.