In a large bowl, whisk together both boxes of pudding mix with 4.25 cups milk and vanilla extract using an electric mixer on medium speed for about 2 minutes, until the mixture thickens to a custard-like consistency. The pudding will continue to set as it cools, so you're looking for a pourable but slightly thick texture at this stage. Set aside to cool slightly while you prepare the other components.

While the pudding cools, slice the bananas into 1/4-inch rounds and toss them gently with lemon juice in a small bowl to prevent browning. Crush about 1/2 cup of the vanilla wafers into fine crumbs for filling gaps and garnish later. Keep the remaining whole wafers separate for layering.

In a 9x13 inch baking dish or similar size, arrange whole vanilla wafers on the bottom and along the sides of the dish, standing them upright or laying them flat depending on your preference. Fill any gaps between wafers with the crushed wafer crumbs from Step 2. This creates a structural base and ensures every bite has that classic wafer texture.

Layer half of the banana slices (from Step 2) evenly over the wafers, then pour half of the pudding mixture (from Step 1) over the bananas, spreading it gently to cover. Repeat with another layer of whole wafers on top, followed by the remaining banana slices and pudding. I like to slightly overlap the banana slices in each layer so the pudding can flow between them and create a more cohesive texture throughout.

Cover the dish with plastic wrap and refrigerate for at least 3 hours, or until the pudding has fully set and the wafers have softened slightly from absorbing the pudding moisture. This resting time allows the flavors to meld and creates that classic creamy pudding texture.

Just before serving, spread or dollop the coco whip generously over the top of the pudding. Arrange fresh banana slices on top for visual appeal and texture contrast, then sprinkle with reserved wafer crumbs. The cold pudding with the whipped topping and fresh banana creates a wonderful contrast of temperatures and textures.