Cook the pasta. Bring a large pot of salted water to a boil.
Cook pasta until just al dente according to package directions. Drain and rinse under cold water to stop cooking and cool it down.
Make the dressing. In a large bowl, whisk together buffalo sauce, ranch, mayonnaise, lemon juice, garlic powder, onion powder, a pinch of salt, and pepper. Taste and adjust heat or tang by adding more buffalo sauce or lemon juice.
Prep the mix-ins. Cook bacon until crisp, then crumble.
Chop chicken, celery, and red onion. Halve tomatoes and grate or crumble cheeses.
Toss the pasta. Add cooled pasta to the dressing and toss until fully coated. This helps the pasta absorb flavor from the start.
Add the good stuff. Fold in chicken, bacon, celery, red onion, tomatoes, and cheddar.
If using blue cheese, gently fold it in last to keep some crumbles intact.
Chill for best flavor. Cover and refrigerate for at least 30–60 minutes. The flavors meld and the dressing sets slightly, making it creamier.
Taste and finish. Right before serving, taste and adjust seasoning. If it looks a little tight, loosen with a splash of ranch or a spoonful of milk.
Garnish with chives or parsley.