Bring a large pot of lightly salted water to a boil. Cook pasta in boiling water until tender yet firm to the bite, 8 to 10 minutes. Drain and set aside.
Combine reserved liquids from pineapple and oranges (about 1 1/2 cups), sugar, beaten eggs, flour, and salt in a medium saucepan over medium heat. Cook until thick, stirring constantly. Mix in cooked pasta. Refrigerate for 8 hours to overnight.
Transfer chilled pasta mixture to a large serving bowl. Stir in pineapple, oranges, whipped topping, and marshmallows. Top with cherries. Keep salad chilled in the refrigerator until serving time.