Combine egg yolks, 1/4 cup plus 2 tablespoons sugar, and salt in top of a double boiler. Place over boiling water. Slowly add half-and-half, stirring with a wire whisk. Bring water to a boil; reduce heat to low. Cook, stirring constantly, until mixture coats a metal spoon. Remove from heat; stir in vanilla. Chill thoroughly.
Fold whipped cream, powdered sugar, and coconut into custard.