Sprinkle bananas, apples and pears with fresh lemon juice. Cut pineapples in half, using curved serrated knife, hollow out pineapple halves leaving ½ inch shell (reserve shells and all juice). Discard core, cut pineapple into ¼ inch cubes.
Transfer to large bowl. Add sliced fruit and toss lightly. Cover and refrigerate up to 2 hours.
For ice cream: Blend cream, powdered sugar and extracts in large bowl. Gradually fold in ice (or fresh clean snow) until mixture is consistency of ice cream. Fold in nuts, add reserved pineapple juice to fruit. Blend in orange juice and Kirsch. Spoon fruit into pineapple shells. Top with ice cream. Serve immediately.
