Heat oven to 350° F. Make Meatballs. In a large bowl, combine ground beef, sausage, bread crumbs, egg, milk and Parmesan. With wet hands, shape into 60 mini meatballs, using 2 tsp of mixture for each.
Heat oil in a large skillet over medium-high heat. Add half the meatballs and cook for 5 minutes, shaking pan to turn meatballs while maintaining their shape. Remove to a plate and repeat with remaining meatballs. Reserve drippings in pan.
Meanwhile, to make Lasagna, bring a large pot of lightly salted water to boiling. Add noodles, 1 at a time, and cook for 10 minutes. Drain and rinse with cool water.
Place skillet from meatballs over medium heat. Add onion and cook, stirring occasionally, 4 minutes. Add garlic; cook 1 minute. Stir in both crushed and diced tomatoes. Simmer 15 minutes. Remove from heat and stir in half the chopped basil. Set aside 3/4 cup of the sauce.
In a medium bowl, blend ricotta, remaining basil, the egg and 2 tbsp of the Parmesan.
Begin layering: Spread 1 cup tomato sauce in bottom of a 13 x 9 x 2-inch baking dish. Top with 4 noodles, overlapping. Scatter half the meatballs over noodles. Pour half the remaining tomato sauce over meatballs. Top with 4 more noodles and spread with ricotta mixture and 1 cup each mozzarella and Fontina. Add 4 more noodles and remaining meatballs. Pour remaining tomato sauce over meatballs. Top with final 4 noodles. Spread with reserved 3/4 cup sauce. Top with remaining 1 cup each mozzarella and Fontina and remaining 2 tbsp Parmesan.
Bake at 350° F for 45 minutes until bubbly and slightly browned. Let stand 15 to 20 minutes before serving.