Prepare all fruit: Drain pineapple and mandarin oranges thoroughly. Halve the grapes if they are large.

In a small bowl, whisk together the Greek yogurt, light whipped topping, and vanilla extract until smooth and well combined. This forms the lightened dressing base.

In a large mixing bowl, gently combine the pineapple chunks, mandarin orange segments, grapes, shredded coconut, and chopped pecans.

Pour the yogurt dressing over the fruit mixture. Use a rubber spatula to carefully fold the ingredients together until the fruit is evenly coated. Avoid over-mixing to keep the fruit intact.

Cover the bowl and chill the ambrosia salad in the refrigerator for at least 1 hour before serving. This allows the flavors to meld.

Taste and adjust sweetness if necessary before serving. Garnish with extra coconut or pecans if desired.