In small bowl, combine all topping ingredients except margarine; mix well. With pastry blender or fork, cut in 3 tablespoons margarine until mixture resembles coarse crumbs. Set aside.
Heat oven to 375°F. Grease 10-inch tube pan. In large bowl, combine 2 cups flour, 1 cup sugar, baking powder, pumpkin pie spice, baking soda and salt; mix well.
Beat eggs in small bowl. Stir in pumpkin, 1/3 cup orange juice, 1/4 cup margarine and 1 teaspoon orange peel. Add to flour mixture; stir just until dry ingredients are moistened. Stir in nuts and dates. Spoon and spread batter in greased pan. Sprinkle with crumb topping.
Bake at 375°F. for 40 to 45 minutes or until toothpick inserted in center comes out clean. Cool 30 minutes; remove from pan.
In small bowl, blend all glaze ingredients, adding enough orange juice for desired drizzling consistency. Drizzle over warm coffee cake. Serve warm or cool.