Step one - In a small mixing bowl, combine Greek yogurt, mayonnaise, sugar, and apple cider vinegar; set aside.
In another mixing bowl, combine cucumber, bell pepper, sweet onion, corn, olive oil, oregano, thyme, garlic salt, onion powder, and lemon pepper; set aside.
Place half of cornbread in bottom of large serving bowl, top with half of vegetable mixture, layer with feta cheese, and dressing. Repeat layers. Cover and chill for 2 to 3 hours before serving.