Grilling heightens the fruit's sweetness and flavor. Slightly firm fruit will stand up to the heat; if you're using ripe fruit, take it from the grill just a few minutes sooner than directed. Garnish with mint sprigs.
Combine 2 cups water and 1/3 cup honey in a small saucepan over medium-high heat. Scrape seeds from the vanilla bean, and add seeds to honey mixture. Discard bean. Bring to a boil. Cook until reduced to 1 1/4 cups (about 15 minutes). Combine whipped topping, cheese, and 1 tablespoon honey, stirring until smooth. Set aside.
Lightly coat both sides of nectarines and plums with cooking spray. Place nectarines and plums, cut side down, on a grill rack coated with cooking spray. Grill 2 minutes on each side or until soft. Place 1 nectarine half and 1 plum half in each of 8 shallow bowls. Top each serving with 1/4 cup cherries; drizzle each with 2 tablespoons honey mixture. Spoon 2 teaspoons cheese mixture over each serving; sprinkle each serving with 3/4 teaspoon nuts.