Preheat a grill to medium (about 400°). Toss pattypans, zucchini, peppers, and tomatoes with 3 tbsp. oil, the chopped thyme and oregano, and salt and pepper to taste.
Thread tomatoes onto skewers.
Grill vegetables until tender and slightly charred on all sides, about 6 to 8 minutes for pattypans, 4 minutes for zucchini and peppers, and 2 minutes for tomatoes.
Put tapenade and grilled peppers in small bowls and place on a large platter. Arrange remaining vegetables around the bowls, along with mozzarella, prosciutto, and melon. Drizzle with remaining 2 tbsp. oil and the vinegar, then sprinkle with herb sprigs and leaves, and flake salt if you like.
Note: Sodium is 938mg without tapenade.