Preheat the grill to medium heat.
In a large bowl, toss the sliced potatoes with olive oil, garlic powder, paprika, salt, and black pepper until evenly coated.
Cut two large pieces of aluminum foil, about 18 inches long. Divide the seasoned fries evenly between the two pieces of foil, placing them in the center.
Fold the sides of the foil over the fries to create a sealed packet. Make sure the packets are tightly sealed to prevent steam from escaping.
Place the foil packets on the grill and cook for 20-25 minutes, turning occasionally, until the fries are tender and golden brown.
Carefully remove the packets from the grill. Open the packets and sprinkle the shredded cheddar cheese on top of the fries. Close the foil packets again and return them to the grill for an additional 5 minutes, or until the cheese is melted.
Remove from the grill, carefully open the packets, and top with chopped green onions and bacon bits if desired. Serve immediately.