Preheat oven to 400°F. Toss potatoes with 1 1/2 tablespoons oil, 1 teaspoon garlic powder, 3/4 teaspoon salt, 1 teaspoon lemon zest, and 1/4 teaspoon pepper in a large bowl. Arrange potatoes in a single layer on a large rimmed baking sheet (set bowl aside). Roast potatoes in oven for 15 minutes. Meanwhile, toss broccoli with 1 teaspoon garlic powder, 1/4 teaspoon salt, 1/4 teaspoon pepper, and remaining 1 1/2 tablespoons oil and 1 teaspoon lemon zest in reserved large bowl. Set aside.

While potatoes roast, stir together egg, milk, oregano, onion powder, chopped chipotles, 2 tablespoons ketchup, 1 tablespoon Worcestershire sauce, and remaining 1 tablespoon garlic powder, 1 1/2 teaspoons salt, and 1 teaspoon black pepper in a large bowl until well combined. Stir in panko, beef, and pork until combined. Divide meat mixture into 6 equal portions (about 5 1/4 ounces each); form into 4- x 2-inch meatloaves.

Remove baking sheet with potatoes from oven. Flip potatoes using a thin metal spatula. Place meatloaves between potatoes on baking sheet. Stir together adobo sauce and remaining 3 tablespoons ketchup and 1 tablespoon Worcestershire sauce in a small bowl until combined; evenly spread over each meatloaf. Return baking sheet to oven, and bake for 10 minutes.

Remove baking sheet from oven; arrange broccoli between potatoes and meatloaves. Return to oven, and bake until potatoes and broccoli are tender, meatloaves are well browned, and a thermometer inserted into thickest portion of meatloaves registers at least 160°F, 15 to 18 minutes. Let stand for 5 minutes.

Divide meatloaves, potatoes, and broccoli evenly among 6 plates. Serve immediately.