To make the crust: Preheat oven to 350 F.  Combine the cookie crumbs, brown sugar and salt in a medium bowl.  Add the butter and toss with a fork until all of the crumbs are moistened (the mixture will be quite wet).  Press into the bottom and up the sides of a 9-inch pie plate.  Refrigerate for about 15 minutes so the crust is firm, then bake until set, about 8-10 minutes.  Transfer to a wire rack to cool completely.To make the filling: In the bowl of a stand mixer fitted with the paddle attachment, beat the cream cheese, confectioners’ sugar and salt on medium speed until light and fluffy, about 2 minutes.   Mix in the peanut butter and vanilla.  (If you don’t have a second bowl for your stand mixer either transfer the cream cheese mixture to another bowl and wash the first, or do the next step with a hand mixer.)  Switch to the whisk attachment on your mixer and beat the heavy cream until you have soft peaks.  Take about 1/3 of the whipped cream and stir it into the cream cheese mixture to lighten it.  Use a rubber spatula to gently fold in the remaining 2/3 of the whipped cream.  Transfer the filling to the cooled crust and spread in an even layer.  Freeze uncovered for at least 4 hours or up to 1 day covered with plastic wrap.To garnish the pie: Put the chocolate in a microwave-safe bowl and heat in 30 second bursts at 50% power, stirring in between each burst.  Continue until the chocolate is melted and smooth.  Transfer to a resealable plastic bag and snip a tiny bit off the corner.  Hold the bag over the pie and drizzle the melted chocolate in a zig-zag pattern.  Put the peanut butter in a small saucepan set over low heat and melt it, stirring frequently.  Add the melted peanut butter to a resealable plastic bag, snip off a corner and drizzle over the pie.  Let stand for about 10 minutes to set.Remove the pie from the freezer about 10-15 minutes before you are ready to serve.  If you have trouble cutting it, running your knife under warm water will help.