I recommend doing the assembly just a few hours before you want to serve the trifle. If you make the trifle too far in advance, the pie crust and Oreo elements will get soggy.
Divide the brownies in half. Crumble one half of the brownies and layer them on the bottom of a trifle bowl.
Measure 2 cups of the banana cream filling and spread the filling over the brownie layer. Make sure to spread the filling all the way to the sides of the bowl.
Drizzle a couple of tablespoons of caramel sauce on the banana filling.
Crumble about half of the Oreo crust and Oreos on top of the filling and caramel.
Measure 2 cups of the whipped cream and spread gently on the Oreo crust.
Repeat these steps for a second layer of each element, finishing with the whipped cream.
Garnish with pie crust crumbs, Oreos and caramel sauce.
Refrigerate until you're ready to serve.