To roast the vegetables:

1. Adjust the oven rack to the middle position and preheat the oven to 400 degrees Fahrenheit.Line a baking sheet with either foil, parchment paper, or a silicone mat to make cleanup easier.Make sure you have enough space in the freezer to accommodate the baking sheet.
2. In a medium bowl, mix together the potatoes, bell pepper, and onion.Drizzle the mixture with olive oil and add 1/2 teaspoon of salt.Toss everything together until the ingredients are evenly coated.
3. Transfer the mixture to a baking sheet that has been prepared.Spread the mixture out in a single layer on the baking sheet.Roast the mixture in the oven until the potatoes are tender, which should take about 20 minutes. 

To make the eggs: 

1. While the vegetables are roasting, whisk together eggs, milk, and the remaining 1/2 teaspoon of salt until well combined.
2. In a large skillet over medium heat, melt the butter until it starts to foam. Add the eggs and cook, stirring occasionally, until they are mostly set but still moist, which should take about 4 to 5 minutes. Then, remove the skillet from the heat. 

To assemble the burritos: 

1. While the eggs and vegetables cool down to room temperature, get ready to assemble. Take 12 squares of aluminum foil and place them nearby. Also, set out the cheese and tortillas.
2. To make a burrito, place a tortilla on a piece of foil. Sprinkle 2 tablespoons of cheese on the tortilla. Add 1/4 cup of roasted vegetables on top of the cheese, followed by 2 heaping tablespoons of scrambled eggs and any additional toppings.
3. Roll the burrito tightly by folding the sides over the filling, and then rolling it up from the bottom.Wrap the burrito tightly in aluminum foil. Repeat the same filling and folding process for the remaining burritos. 

To freeze the burritos: 

1. Place the burritos in a single layer on a baking sheet and freeze them. This will help them freeze faster and more evenly. For long-term freezing, store the frozen burritos in a gallon-sized zip-top freezer bag. 

To reheat and eat the burritos: 

1. Unwrap the burrito and microwave it on high for 1 to 2 minutes. Flip it over once halfway through cooking to ensure even heating.
2. Alternatively, you can heat the burrito in a regular or toaster oven at 350°F for 12 to 15 minutes until it is warmed through.