Slice the pineapple, mango, and papaya into 1/8-inch thick slices and then into bite-size pieces. In a medium bowl, combine pineapple, mango, papaya, orange sections, rum and sugar; toss to combine. Let fruit stand at room temperature for 15 minutes. Divide fruit and liquid among 4 serving dishes. Add 2 small scoops of sorbet to each dish and garnish with the toasted coconut.