Place zucchini, squash, and bell pepper in a large resealable plastic bag. Add enough Italian dressing to coat vegetables. Squeeze out as much air as possible. Seal bag and refrigerate, at least 1 hour. Combine milk, eggs, flour, 1 1/2 teaspoon oil, and salt in a blender. Process until smooth. Cover and refrigerate batter for 1 hour. Heat a skillet over medium-high heat and brush with remaining oil. Pour 1/4 cup of crepe batter into the pan; tilt to completely coat the surface of the pan. Cook, turning once, until golden, 4 to 5 minutes. Let crepe rest on a clean surface until cool to the touch. Repeat with remaining batter. Cut crepes into strips about 1 to 2 inches wide. Preheat a grill for medium heat and lightly oil the grate. Cook zucchini, squash, bell pepper, and ham until vegetables are soft but firm to the bite and ham reaches an internal temperature of at least 160 degrees F (71 degrees C), 8 to 10 minutes. Cut ham into bite-sized pieces. Stack crepes, ham, zucchini, squash, peppers, pineapple, and tomatoes onto skewers in any fashion you prefer.