You can sub fresh pumpkin or sweet potato for the canned puree - cook it and mash it first - then puree the final filling in a food processor to smooth the mixture before filling the pies. Use slightly less than 1 cup of fresh mash, because it's thicker and less watery than canned puree.
This filling recipe is intended for mini pies (which are more fun anyway). It is not quite thick enough to set firmly within a full-sized pie.
For a gluten free version: Skip the crust. Crush up lots of pecans with brown sugar, cinnamon, and a bit of coconut oil and make a parfait.