Preheat the oven to 400ºF.
Cut potatoes and onions into bite-sized pieces (1 in.). Place vegetables along with baby carrots on separate large baking sheets.
Drizzle olive oil over the vegetables and sprinkle with seasoning salt, salt and pepper. Toss until coated in oil and spices.
Transfer baking sheets to the preheated oven and roast for 15 minutes.
In a large bowl, add meatloaf ingredients (set aside 4 Tbsp BBQ sauce) and mix until well combined. Divide into four and shape each into a flattened oval.
After 15 minutes, remove baking sheets and stir vegetables. Push to the side and place 2 meatloaves on each baking sheet. Spread 1 Tbsp BBQ sauce over each loaf.
Return baking sheets to the oven for an additional 20 minutes, or until the internal temperature of meatloaves reaches 160ºF.***
Remove baking sheets from the oven and serve immediately.