An interesting thought. When I was active I was in one congo that had two male newbies come in around the same time. As I recall, they were baptized at the same assembly. One was the most sexually active person I've ever met. He'd starting having sex with his mom when he was pre-schooler. Even though he was single, he screwed several times a day, married and unmarried sisters, brothers (he was truly bisexual), but he especially liked young girls. He made his living as a private hairdresser who went into people's homes in order to work on their hair. He really was like 2 Tim. 3:6 says. Most publishers, and even the elders, saw him as very lovable. In fact the elders reproved, rather than DFed him time and again. Finally they had to DF him, after he'd broken up marriages and made many young teen virgin girls hot-to-trot, eventually the most powerful elder's 12-year old daughter. From what I heard, he really was a great lover. Many sisters said it was the best sex they'd ever had. One even abandoned her husband and kids to run off with him a while. The sisters used to get together and compare notes on the guy. One elder whose attractive wife he failed to seduce called him a stud.
The other guy came in and right after his baptism, married a really cute, but very dumb, single sister who'd had a background of sexual abuse as a girl. She had a very cute 5-year old daughter. Right after their marriage they moved away, and some years later it came out that the guy was having sex regularly with the young girl, in fact, all through her childhood and teen years. Then he dumped them both and took off.
So your idea couldn't help but make me think of these two since they came in together. They even studied with the same pioneer-elder who was quite oblivious of modern culture (ultra loyal, ex-missionary, big-shot ex-bethelite, truly in JWland). The congo was on a basic level very friendly and thus had frequent low-key picnics, get togethers, dinners, etc., so these two guys were often together at them. That congo in particular went out of its way to love bomb those studying, so these guys were always invited to the social events. Whether they planned all this as established pedophiles I do not know. This was before the internet, but I understand that now there are pedo-chatrooms where these people can get together and plan their attacks. So maybe you are onto something here. It's certainly worth pursuing, but other than the anecdotes like mine, how would you collect the info to do so?