Heat the oven to 400°F. Line a baking sheet with parchment paper and arrange the hoagie rolls cut side up.
Brush the cut sides of the rolls lightly with olive oil. Toast them in the oven for 4 to 5 minutes, until lightly crisp.
While the rolls toast, warm the meatloaf slices and marinara sauce in a skillet over medium-low heat. Sprinkle in the Italian seasoning and turn the slices gently to coat. Heat until the meatloaf is warmed through.
Divide the sauced meatloaf among the toasted rolls. Spoon any remaining sauce from the skillet over the slices, then top evenly with the mozzarella and Parmesan.
Return the open sandwiches to the baking sheet. Bake for 5 to 7 minutes, until the cheese is melted and bubbling. Finish with chopped basil and serve warm.