Meanwhile, in a large bowl, combine the mayonnaise, sour cream, buttermilk, parsley, lemon juice, garlic, 2 teaspoons of salt, and 1 teaspoon of pepper. Add the pasta, tomatoes, cheese, peas, pimentos, olives, green onion, and half of the bacon, and toss until well combined. Season salad with salt and pepper, to taste. Top salad with the remaining bacon and serve.