Boil water in a large pot.
Add acini di pepe pasta to the water.
Cook for 8-10 minutes until tender.
Drain well and rinse with cold water.
Set aside to cool completely.
Whisk eggs, sugar, and flour together.
Add crushed pineapple with its juice slowly.
Pour mixture into a saucepan over medium heat.
Stir constantly for 5-7 minutes until thick.
Remove from heat and add lemon juice.
Let it cool in the refrigerator.
Mix cooled pasta with the custard sauce.
Add pineapple chunks and mandarin oranges gently.
Fold in mini marshmallows and coconut.
Add whipped topping and mix until combined.
Refrigerate for at least 4 hours before serving.