Cheesy Bacon Ranch Roasted Potatoes

6 slices bacon, cooked and crumbled or chopped it bits
2 lbs russet potatoes, scrubbed and rinsed, diced into 3/4-inch pieces (about 7 cups)
2 1/2 Tbsp olive oil
1/2 tsp sea salt, more to taste if desired
1/2 tsp freshly ground black pepper
4 oz medium or sharp cheddar cheese, shredded (use 2% if desired)
Light ranch dressing, recipe follows in notes below
2 - 3 green onions, whites discarded, greens chopped
Cooking spray