Unroll pastry on a lightly floured surface. Sprinkle with pecans; lightly roll pecans into pastry. Transfer to a 9-in. pie plate. Line unpricked pastry shell with a double thickness of heavy-duty foil. Bake at 450° for 8 minutes. Remove foil; bake 5 minutes longer. Cool on a wire rack.
In a small bowl, combine the milk, sour cream and sugar substitute. Gradually whisk in dry pudding mix. Fold in whipped topping.
Place lemon juice in a small bowl. Slice bananas into juice and stir gently to coat. Set aside 1/3 cup; spoon remaining banana slices into the crust. Top with pudding mixture, blueberries and reserved banana slices. Cover and refrigerate for 30 minutes before serving.