when we moved in they didn’t have 7 kids.
I don’t understand your point; should they have stopped having kids while you were their tenants? (I’m sure you don’t mean that.)
Your complaint about the construction was valid. The only way I could understand the validity of your other complaint is if after having more children (producing more noise) they didn’t let you out of the lease.
Your conduct regarding the paranoid landlady was quite admirable.