Preheat oven to 425°F. Line a large rimmed baking sheet with parchment paper.
Place cabbage on the prepared baking sheet. Drizzle with 2 tablespoons oil and season with ¼ teaspoon each salt and pepper. Roast for 25 minutes.
Turn the wedges, separating the leaves a little bit to ensure even cooking. Place feta block in the middle of the pan; drizzle it with 1 tablespoon oil and sprinkle with thyme and paprika. Continue roasting until the feta is softened and the cabbage is very tender, about 8 minutes more.
Combine avocado, ¾ cup parsley, vinegar, ¼ teaspoon salt and the remaining ⅛ teaspoon pepper in a blender. Process until just combined. With the motor running, slowly drizzle in ⅓ cup oil.
Bring water to a boil in a small saucepan. Add couscous and the remaining ¼ teaspoon salt and stir to combine. Cover and remove from heat. Let stand for 5 minutes. Add lemon zest, lemon juice and the remaining 1 tablespoon oil; fluff with a fork.
Assemble the bowls with the couscous, cabbage, feta and eggs. Dollop the dressing on top and sprinkle with the remaining ¼ cup parsley.
