Make the crust: Preheat oven to 350 degrees. Combine wafer crumbs, butter, brown sugar, and salt. Press mixture firmly into bottom and up sides of a 9-inch deep-dish pie plate. Bake until set, 8 to 10 minutes. Let cool on a wire rack.
Make the filling: Beat cream cheese, confectioners' sugar, and salt with a mixer on medium speed until fluffy. Beat in peanut butter and vanilla.
Beat heavy cream until soft peaks form. Whisk 1/3d of the whipped cream into the peanut butter mixture, then gently fold in remaining whipped cream. Spoon filling into cooled crust. Freeze, uncovered, at least 4 hours (or overnight, covered with plastic wrap).
Place melted chocolate in a resealable plastic bag. Snip tip from one corner of bag to make a very small opening. Holding bag about 5 inches above pie, drizzle melted chocolate over top. Repeat with melted peanut butter. Let stand 10 minutes before slicing.