Whisk together 1/2 cup of Worcestershire sauce, liquid smoke, and lemon pepper in a bowl. and pour into a resealable plastic bag. Add the lamb cubes, coat with the marinade, squeeze out excess air, and seal the bag. Marinate in the refrigerator for 1 hour. Prepare the dipping sauce by whisking together the salad dressings, 1 teaspoon Worcestershire sauce, mustard, ketchup, and onion powder in a small bowl. Refrigerate until ready to serve.