Combine all crust ingredients. Reserve 5 ounces. Press remaining crumbs (about 12 ounces per pie) over bottom and up sides of four 9-inch pie pans. Bake for 10 minutes at 400°F. Cool completely.
Mix pumpkin, brown sugar, corn syrup and pumpkin pie spice in a large bowl. Fold in softened ice cream. Pour mixture into crusts. Top with reserved crust crumbs.
Cover lightly. Freeze until firm, 2 hours or overnight. Remove from freezer 15 minutes before serving.