1.Place Oreo cookies in a food processor fitted with the blade attachment and pulse until fine, sandy crumbs form, 12 to 15 (1-second) pulses. Add melted butter and a pinch of salt. Pulse until the crumbs begin to stick together, 6 to 8 (1-second) pulses.
2.Transfer the crumbs to a regular 9- or 10-inch pie plate (not deep dish). Use the bottom of a measuring cup or your fingers to press evenly into the bottom and up the sides of the plate. Refrigerate until firm, about 30 minutes. Meanwhile, let chocolate ice cream and coffee ice cream sit at room temperature until softened, 20 to 30 minutes.
3.Coarsely chop until you have 1/2 cup toffee. Transfer the chocolate ice cream into the crust and spread into an even layer. Freeze for 5 minutes. Dollop fudge sauce in spoonfuls over the ice cream and spread into an even layer. Sprinkle with half of the toffee. Freeze for 5 minutes. Transfer the coffee ice cream over the toffee and spread into an even layer. Cover and freeze until very firm, at least 2 hours or up to 1 month.
4.When ready to serve, place heavy cream, powdered sugar, and vanilla in the bowl of a stand mixer. Beat with the whisk attachment on medium speed until soft peaks form, 2 to 5 minutes. Spoon the whipped cream onto the pie, swirling as desired. Sprinkle with the remaining toffee.