Preheat the oven to 350 degrees, placing the top oven rack into the middle slot in your oven.
Combine all of the ingredients for the crust in a food processor until the mixture turns into a ball of dough. You can either press this mixture into the pie pan with clean hands and try to make it as even as possible, or, you can roll out the dough between two sheets of parchment paper and attempt to flip the crust into the pie dish. If the crust breaks a part a bit, it's okay. Simply use your fingers to repair it. It's not fussy, and will totally taste the same.
Add the apples, lemon juice, apple pie spice and arrowroot starch into a mixing bowl and toss until everything is fully mixed. Set aside.
Clean out your food processor and wipe it dry. Now, combine all of the ingredients for the pumpkin pie filling and process it on high for a minute or so, or until the mixture is completely smooth.
To make the crumble that will top the pie, add all of the crumble ingredients to a mixing bowl. Use your fingers to break up the butter into the mixture. This should make it nice and crumbly . You don't want to overwork it, or the butter will melt too much and it will no longer be that crumble texture that you desire.
Place your crust filled pie dish on top of a baking sheet. I do this just in case any spill-over happens in the baking process. Fill the crust with the apples first, and then pour the pumpkin pie filling over the apples evenly. Once both of those fillings are inside the crust, sprinkle the crumble on top.
Place the pie on the rack in the oven that you've positioned in the center. Bake for about 60-80 minutes, checking on it in 20 minute intervals. You want the crust and the crumble to brown, and for the pumpkin pie to set just enough for that there is a slight jiggle in the center. It should be like a custard, and no longer liquid.
Remove the pie from the oven once it's baked through. Allow it to cool on the counter for about two hours before putting it into the refrigerator. You could serve the pie at room temp, but I find that it sets up really nicely if refrigerated for a couple more hours or overnight. Cover the pie loosely with tin foil and allow it to firm up in the fridge.
Once chilled through, serve as you would any other pumpkin pie. It goes great with some whipped cream, or coconut whipped cream on top! A scoop of vanilla ice cream might be even better. Enjoy!