That is a good point about gossip about non-JWs...it is part and parcel of the JW religion to make notes about return visits and Bible studies, including intimate details about their private lives (even bedroom details of married couples), and troubleshoot these things with other JWs. "So-and-so has a problem with...how do I approach this with them?"
I remember years ago a young pioneer placed a Mankind's Search For God book with some folks in a fast food restaurant. He related this "experience" to the other pioneers. Two pioneer women called on them later that day or the next day. They were buzzing with enthusiasm when they learned they had received the book and exclaimed the young pioneer's name who placed it with them. The non-JWs at the door said something like, "You know? You talk about these things with each other?"
And of course, growing up with elders in my family I would overhear things I should not have.