Preheat oven to 400 degrees F. Line a baking sheet with parchment paper and set aside.
In a medium bowl, toss together the zucchini, 1 tablespoon olive oil, 1/2 teaspoon salt, 1/2 teaspoon black pepper, garlic powder, onion powder, oregano, and red pepper flakes. Pour out onto the prepared baking sheet, and move to one side.
Place the eggplant on the baking sheet, off to one side and drizzle with 1 tablespoon olive oil. Season with the remaining salt, pepper and za’atar if using. Roast until the zucchini and eggplant have begun to brown, about 15 minutes.
In a large bowl, combine the shrimp, harissa and the remaining olive oil. Pour the shrimp onto the baking sheet, along with the veggies, off to one side. Return to the oven and roast for another 10 to 12 minutes.
Sprinkle the shrimp with feta, and parsley. Serve with store-bought tzatziki and pita, if desired.