Preheat oven to 400°. Toss zucchini and peppers with oil and seasonings; transfer to a 15x10x1-in. pan. Roast until tender, 25-30 minutes, stirring once. Stir in tomato; cool slightly., Trim ends from bread; cut bread into 1-in. slices. In a greased 13x9-in. baking dish, layer half of each of the following: bread, roasted vegetables and cheeses. Repeat layers. Whisk together eggs and milk; pour evenly over top. Refrigerate, covered, 6 hours or overnight., Preheat oven to 375°. Remove casserole from refrigerator while oven heats. Bake, uncovered, until golden brown, 40-50 minutes. Let stand 5-10 minutes before cutting.