Cut up fruit, it can be prepared a day ahead except for bananas. Section grapefruit and oranges try to get whole pieces. Peel papaya and mango and cut into 1/4-1/2 inch wide strips 1-2 inches long.
After all fruit has been cut drain fruit well (at least one hour) in strainer. Reserve the drained fruit juice for another use. Mix all of the fruit including bananas gently in a large bowl with rubber spatula to combine.
Prepare lemon yogurt sauce. Mix lemon yogurt with 2-3 Tablespoons of the reserved pineapple juice. Sauce thickness depends on your individual taste. Using 3/4 cup or 1 cup measure, divide fruit into six or eight equal servings centered in a mound or design as you'd like on individual plates, luncheon size. Pour 2/3 Tablespoons sauce randomly over fruit. Garnish each plate with 2 teaspoons toasted coconut either around the sides of the mound of fruit or on top of fruit. Add macadamia nuts around fruit.