Steps:

1. 1 Mix onion, parsley, yogurt, fennel seeds, salt, and pepper in a large bowl just to combine. Add pork and mix with your hands (or a wooden spoon) until well blended but take care not to overmix, or meatballs could be dense.
2. 2 Using your hands, lightly pack meatball mixture into tangerine-size balls (about 1½" in diameter) and place them on a rimmed baking sheet.
3. 3 Heat 2 Tbsp. oil in a large heavy pot over medium-high. Working in batches and adding more oil if needed, add meatballs to pot, making sure to leave enough space between them so you can move them freely, and cook, turning occasionally to help them keep their shape, until evenly browned on all sides, 5–8 minutes. Transfer to a clean rimmed baking sheet.
4. 4 Add shallots, garlic, and half of fennel to pot (no need to wipe out). Season with salt and pepper and cook, stirring occasionally and reducing heat as needed, until vegetables are softened and starting to brown, 10–12 minutes.
5. 5 Add broth and 2 Tbsp. vinegar to pot and bring liquid to a simmer. Return meatballs to pot along with any juices that have accumulated on baking sheet and simmer long enough to let flavors meld, 6–8 minutes.
6. 6 Meanwhile, toss pea shoots, dill, remaining sliced fennel bulb and remaining 1 Tbsp. vinegar in a medium bowl; season with salt and pepper. Set salad aside.
7. 7 Just before serving, add sugar snap peas and English peas to broth and cook until no longer raw, just a minute or two (you want them to retain a little bit of bite).
8. 8 Spoon fregola into bowls and ladle meatballs, vegetables, and broth over. Top with reserved pea shoot salad and sprinkle with Aleppo-style pepper if desired. Serve lemon wedges and Parmesan alongside.