Cook bacon in skillet over medium 8 to 10 minutes until crisp; paper-towel drain.
Boil pasta with tablespoon salt until fully tender, adding broccoli last minute. Drain, cool-rinse, and drain thoroughly.
Mix yogurt, mayonnaise, buttermilk, lemon juice, chives, dill, garlic powder, onion powder, dressing salt, and pepper.
Fold dressing through pasta and broccoli with half bacon. Cover; refrigerate 30 minutes, included in prep time.
Gently stir in remaining bacon just before serving. Refrigerate leftovers within 2 hours.