Heat a gas grill to medium-high or prepare a charcoal grill with medium-hot coals. Coat corn and peppers with nonstick cooking spray. Grill corn and peppers, turning often, until lightly charred, about 10 minutes.
Remove from grill. Place peppers in a paper bag; let cool. When cool, remove skins, seeds and inner membranes. Chop coarsely. Cut corn from cobs; combine with peppers, olive oil, lime juice, cilantro, salt and pepper. Stir well.
Place cutlets in a large resealable plastic bag. Add buttermilk and lime juice. Marinate at least 1 hour in refrigerator or up to 4 hours.
Combine cornmeal and bread crumbs in a large shallow plate. Remove a cutlet from the marinade; let excess drip back in. Place in cornmeal mixture and turn to coat completely. Set on plate in a single layer; repeat, using remaining mixture.
Heat large nonstick skillet over medium-high heat; coat with nonstick spray. Add 2 teaspoons of oil and tilt to coat bottom. Add enough cutlets to cook in a single layer; sprinkle with a little salt and pepper. Cook about 3 minutes per side; remove to a paper-towel-lined plate. Repeat, adding more nonstick spray and oil. Let cutlets cool, turning on paper towel occasionally. Refrigerate, covered with plastic wrap, up to 1 day. Remove 30 minutes before serving.