Cook the acini di pepe pasta according to package directions, then drain and rinse with cold water.
In a medium saucepan, whisk together sugar, flour, and salt.
Add beaten eggs and pineapple juice to the saucepan, then cook over medium heat, stirring constantly, until thickened.
Remove from heat and stir in lemon juice and vanilla extract.
In a large bowl, combine cooked pasta with the pudding mixture, stirring gently to coat.
Cover and refrigerate for at least 4 hours or overnight.
After chilling, gently fold in pineapple chunks, mandarin oranges, marshmallows, and cherries.
Fold in the whipped topping last, creating a creamy, fluffy texture throughout.
Return to the refrigerator for at least 2 more hours before serving.