Line a baking sheet with parchment paper; set aside.
In a large bowl, whisk the flour, both sugars, baking powder, spices, and salt together. Use a cheese grater to grate the butter on top of the dry ingredients. Add the cream cheese. Then use a fork or pastry blender to cut the butter and cream cheese into the flour. The mixture should resemble coarse crumbs.
In a medium bowl, whisk the pumpkin, 1/4 cup heavy cream, yogurt (or sour cream), egg, and vanilla together until combined. Pour wet ingredients over the dry ingredients, and stir with a spatula until dough comes together. You might need to use your hands to mix the rest of the loose flour into the dough. Turn dough out onto a floured surface.
Laminate the dough by shaping it into a rectangle. Fold it in half, press it down slightly, then turn the dough 90 degrees and fold in half again. Repeat this process 2-3 more times before shaping the dough into an 8-inch disc that's about 1.5 inches tall. Using a sharp knife or bench scraper, slice into 8 even wedges. Place them on the baking sheet 2 inches apart. Chill in the refrigerator for at least 1 hour.**
Preheat oven to 400ºF. Brush scones with heavy cream. Bake for 20-23 minutes or until golden brown around the edges and lightly browned on top. Remove scones from the oven and allow to cool at least 5 minutes before drizzling icing on top.