How to Make It
Place 1 cup dried shrimp in a small bowl. Add warm water to cover, and let stand for 30 minutes; drain.
Combine soaked shrimp, pork bones, pork tenderloin, chicken drumsticks, 2 bunches whole scallions, onion, sweet potato, carrot, bok choy, daikon, garlic head halves, 2 tablespoons soy sauce, fish sauce, and 1 tablespoon sugar in a stockpot. Add 6 quarts water and bring to a boil over high. Reduce heat to medium-low, and simmer until an instant-read thermometer inserted in thickest portion of tenderloin registers 140°F, about 30 minutes. Using tongs, transfer tenderloin to a plate and let cool slightly; cover and refrigerate. Continue to simmer broth until well flavored, about 2 hours and 30 minutes.
Meanwhile, place a fine wire-mesh strainer over a small heatproof bowl. Heat 1/4 cup oil in a small skillet over medium-high. Add chopped garlic, and cook, stirring occasionally, until garlic is golden and oil is hot and fragrant, about 3 minutes. Strain into prepared bowl. Reserve fried garlic.
Heat 2 tablespoons olive oil in a large skillet over medium. Add ground pork, season with salt and pepper, and cook, stirring occasionally, until cooked through and browned, about 10 minutes. Scrape into a medium bowl. In the same skillet, heat remaining 1 tablespoon olive oil. Add remaining 1/2 cup dried shrimp, and cook over medium-high, stirring often, until shrimp are bright pink and crisp, about 2 minutes.
Fill a large pot with water, and fit with a colander. Bring to a boil. Blanch bean sprouts 10 seconds; transfer to a medium bowl. Return water to a boil and add raw shrimp; cook until just pink, 2 to 3 minutes. Drain and transfer to a medium bowl.
Using tongs, remove scallions and chicken drumsticks from stockpot and transfer to a medium bowl. Pour broth through a fine wire-mesh strainer into a large pot; discard solids. Bring to a simmer and season with salt. Add tenderloin and cook until warmed through, about 5 minutes. Transfer tenderloin to a work surface and thinly slice. Coarsely shred chicken meat, and discard skin and bones.
Cook vermicelli in a large pot of boiling water until al dente; drain. Rinse under cool water. Pat dry. Toss with reserved garlic oil and 1 teaspoon reserved fried garlic.
Divide lettuce leaves among 8 large bowls. Top each leaf with noodles, and ladle broth over noodles. Top with sliced pork tenderloin, shredded chicken, ground pork, cooked shrimp, dried shrimp, whole scallions, and remaining fried garlic. Serve with bean sprouts, sliced scallions, cilantro, pickled chiles, sliced chiles, chile paste, lime wedges, soy sauce, sugar, salt, and pepper.