Spray grill grate and 8x8-inch piece of aluminum foil with cooking spray; set aside. Preheat grill for medium-low heat. Stir together melted butter, 2 tablespoons brown sugar and cinnamon in small bowl.
Brush banana, peaches and pineapple with butter mixture. Dip strawberries in balsamic vinegar; roll in remaining 1 tablespoon brown sugar, coating both sides. Grill banana, peaches and pineapple 3 minutes on each side or until grill marks develop. Remove from grill; set aside and keep warm. Place foil on grill; add strawberries. Grill 2 minutes on each side or until hot and slightly tender.
Remove peel from banana. Place grilled fruit in sundae cups; top each evenly with ice cream. Drizzle with syrup and top with nuts, if desired. Top each with Reddi-wip before serving.