Grilled Ratatouille Salad

Name: Grilled Ratatouille Salad
Ingredients: 1 large garlic clove, minced; 2 tablespoons lemon juice; 2 tablespoons Dijon mustard; 1 tablespoon rice wine vinegar; Salt and ground black pepper; ¾ cup extra-virgin olive oil, divided; 4 ounces (about ¾ cup) crumbled feta cheese, divided; 1 large eggplant, trimmed and sliced about ½-inch thick; 2 medium zucchini, trimmed and sliced on the diagonal about ½-inch; 2 medium red onions, trimmed and cut into thick slabs; 2 yellow or orange bell peppers, quartered, stemmed and seeded; 4 Italian plum tomatoes, halved; ¼ cup chopped fresh oregano