Drain the peppers and cut into 1-inch pieces.
Slice the scallions and 2 cloves garlic.
Combine the vegetables in a bowl with the shrimp, 2 tablespoons oil, 1/2 teaspoon salt, and 1/2 teaspoon pepper.
Divide the mixture among 4 resealable plastic freezer bags, top with the Feta (crumbled), and freeze, for up to 3 months, until ready to cook.
Heat oven to 400° F.
Remove the shrimp mixture from the bags (you'll need one bag per serving) and place in individual baking dishes or a large casserole, making sure the Feta is on top.
Bake until the shrimp are cooked through and the Feta begins to brown, about 20 minutes.