Preheat the oven to 350°F (175°C). Grease and flour two 8-inch round cake pans.
Whisk together the cake flour, baking powder, baking soda, and salt in a bowl. Set aside.
Cream the butter and sugar together for a full 3 minutes until pale and fluffy.
Add the eggs one at a time, beating well after each addition, then mix in the vanilla and 1 tablespoon of pickle brine.
Alternate adding the flour mixture and buttermilk to the batter in three additions, starting and ending with flour, mixing just until combined.
Divide the batter between the prepared pans and bake for 24–28 minutes, until a toothpick comes out with a few moist crumbs.
Cool the cakes in their pans for 10 minutes, then turn out onto a wire rack to cool completely, about 1 hour.
Level the cooled cake layers with a serrated knife, reserving 1 cup of the trimmed crumbs for the cake pop pickles.
Beat the softened butter and cream cheese together until smooth. Add the powdered sugar in two batches on low speed, then mix in the vanilla, salt, and strained pickle brine.
Divide the frosting into three bowls and tint each a different shade of green, from deep to pale.
Frost the cake in an ombre effect, with the darkest shade at the base blending up to the palest shade at the top.
Mix the reserved cake crumbs with 2–3 tablespoons of frosting until it holds together like dough. Shape into small pickle-spear ovals and chill for 15 minutes.
Melt the candy coating and dip each cake pop pickle, texturing the surface with a toothpick while the coating is still wet.
Once the coating has set, arrange the cake pop pickles on top of and around the base of the cake, tucking in fresh dill sprigs for the finished look.