Preheat the oven to 425°F. Lightly spray 2 baking sheets with cooking spray.
Arrange the zucchini and yellow squash in an even single layer on the prepared baking sheets. Brush with the olive oil and sprinkle with 1 teaspoon of the salt. Roast until tender and browned, 25 to 30 minutes. Remove from the oven and set aside to cool.
Reduce the oven temperature to 350°F. Spray a deep 9 x 13-inch lasagna pan with cooking spray.
Combine the ricotta, half of the mozzarella, the Fontina, egg, basil, oregano, pepper, and the remaining 1 teaspoon salt in a large bowl. Stir well.
To assemble: Cover the bottom of the pan with one-quarter of the noodles, overlapping them slightly. Spread half of the ricotta mixture over the noodles. Follow with half of the roasted squash, and top with a layer of noodles. Spread with half of the tomatoes and half of the remaining mozzarella. Top with another layer of noodles, the remaining ricotta mixture, the remaining squash, and another layer of noodles. Finish with the remaining tomatoes, the rest of the mozzarella, and the Parmesan.
Lightly spray one side of aluminum foil with cooking spray. Cover the lasagna with the foil, sprayed side down, so that the melted cheese wont stick. Bake 30 minutes, remove the foil, and continue baking until golden brown and bubbly, 10 to 15 minutes. Let rest 10 minutes before slicing.