Preheat oven to 325°F (160°C). Toast coconut on a sheet pan for 10-12 minutes, stirring halfway, then cool.
Cream sugars, butter, coconut oil, egg, lemon zest, and vanilla bean paste until well combined.
Mix in flour, salt, and baking soda; fold in toasted coconut, rice cereal, and oatmeal. Drop scoops onto baking sheets and bake for 18-22 minutes until golden.
Prepare glaze by mixing powdered sugar, lemon juice, half and half, and vanilla bean paste until smooth. Drizzle over warm cookies and cool completely.
Notes
Keep an eye on the coconut while toasting to prevent burning.