Preheat the oven to 400°F with a rack in the center position. Line a rimmed sheet pan with parchment.
Wash and pat dry the potatoes. Prick each potato 6 or 7 times with a fork, then arrange them on the prepared sheet pan. Bake until fork tender, about 60 minutes. Let cool for about 5 minutes.
Reduce the oven temperature to 350°F.
Cut the potatoes in half. Keeping the potato skins intact, use a spoon to scoop out the inside of the potatoes and transfer to a large bowl. Arrange the skins on the prepared sheet pan.
To the bowl with the potatoes, add ¾ of the bacon, 1 cup cheddar, half of the blue cheese, sour cream, heavy cream, ¾ of the green onions, garlic powder, onion powder, salt, and pepper. Mix until fully combined.
Spoon the potato mixture into the skins, dividing evenly. Sprinkle with remaining cheddar cheese. Bake until the cheese is melted, 15-20 minutes.
Top with remaining blue cheese, remaining bacon and remaining green onions. Serve warm.