In a large bowl, combine brown sugar, corn syrup, and cane syrup. Whisk in melted butter and eggs until well combined. Whisk in vanilla extract and salt. Sprinkle pecans and dates into bottom of pie crust. Pour brown-sugar mixture on top of pecans and dates. Bake for 45 minutes to 1 hour or until center is set. If necessary, cover loosely with aluminum foil for the last 20 to 30 minutes of baking to prevent excess browning. Let cool completely on a wire rack before serving. Garnish with whipped topping, chopped pecans, and ground cinnamon, if desired.