For the biscuits: Adjust oven rack to middle position and preheat oven to 425F. Line rimmed baking sheet with parchment paper. Whisk together 3 cups flour, baking powder, sugar, 1 1/2 tsp salt, and baking soda in a large mixing bowl. Add 1 stick chilled butter to bowl, and using 2 dinner knives cut into dry ingredients until mixture resembles coarse meal.
Add 11/2 cups buttermilk and stir with wooden spoon until combined. If mixture looks dry , add more buttermilk, 1 Tbsp at a time until mixture comes together.
Lightly flour a work surface and stamp out 6 biscuits. Arrange them 1 inch apart on prepared baking sheet. Bake biscuits until golden, 12-15 minutes. Transfer to a cooling rack.
For the fried chicken: Heat oil in a Dutch oven or large skillet with tall sides to 350F. With a sharp deboning knife, debone the chicken thighs.
Combine 1 cup buttermilk, 1 1/2 tsp salt, 2 tsp lemon zest, and 2 tsp lemon juice in a medium bowl. Whisk together 1 1/2 cup flour, garlic powder, onion powder, pepper, paprika, and cayenne in a large plate.
One piece at a time dip chicken in buttermilk, then dredge in flour. Shake off excess, then transfer to another plate. Cook chicken in 2 batches, turning occasionally, until crisp and deep golden and an instant thermometer inserted into the thickest part registers at least 165F. Transfer fried chicken to a paper towel lined plate.
For the honey butter and assembly: Stir 6 Tbsp softened butter, honey, and 1/4 tsp salt in a small bowl with a fork until smooth and combined. Cut biscuits in half and spread both halves with honey butter. Place 1 piece of chicken on halves, then top with pickle sliced if using and biscuit top. Serve immediately. Enjoy!