Prepare the cheesecake: Preheat the oven to 350 degrees F. Combine the wafer crumbs, ground pecans and melted butter in a bowl. Press into the bottom of a 12-inch springform pan. In a food processor fitted with the metal blade, mix the cream cheese until smooth. Add the brown sugar and process until blended. Add the eggs one at a time, processing until fully incorporated, then blend in the heavy cream. Add the flour, salt, cinnamon and vanilla and blend until smooth. Add the pumpkin and blend until smooth.
Pour the filling over the crust in the pan. Bake 1 hour, 15 minutes, or until the cheesecake is just set. Remove from the oven. Use a knife to loosen the cake from the side of the pan; this will prevent it from splitting down the center. Let cool completely before slicing.
Meanwhile, make the toppings: Combine the whipped cream and bourbon in a bowl and mix until blended. For the chocolate sauce, combine the half-and-half and butter in a small heavy-bottomed saucepan over medium heat. Heat until a thin, paper-like skin appears on top; do not boil. Add the chocolate chips and vanilla and stir until the chocolate melts and the mixture is smooth. Remove from the heat and let cool.
Remove the side of the springform pan and slice the cheesecake. Top each piece with a drizzle of chocolate sauce and some bourbon whipped cream.