Re: Yappy pups!
You don't let children do whatever they want, else they will grow up disrespectful and uncaring, and IMO puppy's are not much different.
The neighbours should begin teaching the new one very gently from day one.
Apart from not being fair to the neighbours, it is also not fair to let a new boisterous young pup plague the life out of the old Lab either. The oldies need to rest more.
When the old dog has had enough and finally turns on the youngster, who will they blame?
I think if it continues you will need to say something Tabby.
I can't tell you exactly what, because I don't know the family like you do, but you could try something casual like . . . "I
hear you have a new puppy!" rather than "I
see you have a new puppy" might be an opener? (With a sweet smile of course).
Maybe they don't even realise you can hear them so loudly, but I would let them know you can before it becomes a habit that won't be easy to break.