Prepare Meatloaf: Preheat oven to 325°. Pulse chopped bacon 4-5 times in a food processor until finely chopped. Combine bacon, pork, and next 8 ingredients, using hands. Transfer mixture to a lightly greased 8 1/2 x 4 1/2 inch loafpan.
Bake at 325° for 1 hour and 45 minutes to 2 hours or until a meat thermometer inserted in the center registers 160°.
Prepare Gravy: Cook the bacon pieces in a large cast-iron skillet for 8 to 10 minutes or until crisp; remove bacon, and drain on paper towels, reserving the drippings in the skillet.
Increase the temperature to medium-high. Add tomatoes, cut sides down, and onion slices. Cook 6 to 7 minutes on each side or until charred. Remove from the heat. Pulse tomatoes, onions, vinegar, and next 2 ingredients in a food processor just until coarsely chopped and combined. Stir in bacon.
Prepare Potatoes: Preheat broiler with oven rack placed in the middle position. Bring Yukon gold potatoes, 1 tbsp sea salt, and water to cover to a boil in a large saucepan over medium-high heat; reduce heat to medium, and cook 15 minutes or until tender. Drain.
Combine potatoes, panko, and the next 5 ingredients in a large bowl; mash with a potato masher to the desired consistency.
Place 12 meatloaf slices on a lightly greased rack in a broiler pan. Spoon potato mixture generously over the meatloaf. Broil 4 to 5 minutes or until potatoes are golden and crisp. Serve between toasted bread slices with gravy.