You can use pureed squash instead of pureed pumpkin. And if you'd like, you can substitute more squash puree or applesauce for the pie apples.
1/2 c pureed squash or pumpkin
1 t cinnamon, nutmeg or ground cloves (to taste)
Plain yogurt can be substituted for vanilla yogurt.
Either purchase pumpkin seeds or save them after carving pumpkins.