Combine shallots, lemongrass, soy sauce, fish sauce, chili paste, salt, sugar, and five-spice powder in a large bowl. Add pork shoulder and pork belly and toss to coat. Cover and chill at least 3 hours. Remove pork from marinade, scraping excess back into bowl; set marinade aside. Heat oil in a large Dutch oven or other heavy pot over medium-high heat. Cook pork, turning occasionally, until browned all over, 1015 minutes; transfer to a plate. Pour off all but 1 tablespoon fat from pot. Add garlic and cook, stirring, until fragrant but without taking on any color, about 1 minute. Add reserved marinade and 4 cups water and bring to a boil. Add pork, reduce heat, and simmer, partially covered, turning pork occasionally, until fork-tender but not falling apart, 11 1/2 hours. Let cool in liquid. DO AHEAD: Pork can be marinated 1 day ahead of braising; keep chilled. Pork can be braised 2 days ahead; cover and chill. Heat 1/2 cup oil in a small skillet over medium-high heat. Working in batches, fry wonton wrappers until golden brown, about 30 seconds per side. Transfer to paper towels to drain; season with salt. Cook noodles according to package directions. Using tongs or a spider, transfer noodles to a colander and run under cold water to stop cooking; transfer to a large bowl. Toss with remaining 1 tablespoon oil; set aside. (Keep pot of boiling water handy for reheating noodles.) Remove pork from braising liquid and slice 1/4″ thick. Bring braising liquid to a boil (it will be concentrated, like the juices in a roasting pan). Add 1/2 cup water. The flavor should still be intense and slightly salty; adjust with more water if needed. Simmer 2 minutes, remove from heat and add sliced pork. Let cool slightly. Just before serving, return noodle cooking water to a boil. Place noodles in a fine-mesh sieve and lower into hot water to reheat, 30 seconds. Divide noodles among bowls. Place bean sprouts in sieve and cook in same pot of water 30 seconds; drain and place on top of noodles. Remove pork from cooking liquid and place on top of noodles. Ladle some cooking liquid over. Serve with chile, lime wedges, wontons, a handful of herbs, and a dab of chili paste. DO AHEAD: Wontons can be fried 5 days ahead. Let cool; store airtight at room temperature.