You agent sounds like he's covering his own ass, not yours. But since you seem set on trusting him, then I guess you just ask his advice about the neighbor noise and follow that as well.
To me, a question about noise strongly implies illegal or truly problematic noise. If you aren't calling the police (or at a minimum, knocking on their door telling them to STFU, and probably more than a couple times a year), then it's not a noise *problem*, it's just sounds. Otherwise, you'd have to report every bird, backfiring car, motorcycle that drives by, instance kids playing outside and literally any noise you hear, not? If you are reporting noises, then all those qualify. If you are reporting noise problems then none of those do, and nor do, IMO, the occasional sounds of a person living on your "roof" or sharing a wall.
And by the same logic, if you have to report this sink then, they don't you need to report every running toilet, dripping sink, loose drawer pull that you tightened, door squeak to which you applied WD-40.... All problems the house has ever had that have been fixed.