Preheat the oven to 350 degrees F (175 degrees C). Grease two 9x5-inch loaf pans.
Stir flour, cinnamon, nutmeg, and salt together in a bowl until blended.
Whisk sugar, oil, melted butter, honey, eggs, and vanilla together in a large bowl. Stir in zucchini, walnuts, and coconut. Add flour mixture and stir until well combined. Divide batter between the prepared loaf pans.
Bake in the preheated oven until a toothpick inserted in the center comes out clean, about 1 hour. Cool completely. If desired, store loaves overnight in plastic bags for the best flavor.