For vanilla wafer crust: Preheat oven to 350°F Combine all ingredients in processor; blend until mixture resembles moist crumbs, about 1 minute. Transfer to 9-inch-diameter glass pie dish and press mixture onto bottom and up sides (not rim) of dish. Bake crust until golden brown, about 12 minutes. Remove from oven; press crust with back of spoon if puffed. Cool crust completely.
For vanilla pudding filling: Whisk sugar, cornstarch, and salt in heavy medium saucepan until no lumps remain. Gradually whisk in cream, then milk over medium heat. Add yolks and scrape in seeds from vanilla bean; whisk to blend. Cook over medium heat, whisking constantly, until pudding thickens and boils, about 5 minutes. Add butter and stir until melted. Spread warm pudding in cooled crust. Chill until filling is cool, about 1 hour.
Thinly slice 3 bananas on diagonal. Combine banana slices and 2 tablespoons orange juice in medium bowl; toss to coat. Transfer banana slices to paper towels and pat dry. Arrange enough banana slices in single layer over vanilla custard filling to cover completely.
For peanut butter layer: Using electric mixer, beat cream cheese and powdered sugar in medium bowl until smooth. Beat in vanilla, then peanut butter. Beat cream in another medium bowl until firm peaks form. Fold large spoonful of whipped cream into peanut mixture to loosen, then fold in remaining cream in 2 additions. Spread peanut butter layer evenly over bananas. Chill at least 3 hours. DO AHEAD: Can be made 8 hours ahead. Keep chilled.
Thinly slice remaining banana on diagonal. Toss with remaining 1 tablespoon orange juice, then pat dry with paper towels. Arrange banana slices around top edge of pie. Sprinkle peanut brittle over bananas, if desired, and serve.