The part about the leaders meeting with the devils, Lex only told Miranda, and through his spirit sense. It would be in bad taste if he began spreading confidential information willy-nilly.
In fact, this was not a new development.
Since the original five families had been dethroned and replaced by the council of new order, some of the original members of the five ruling families started meeting with the devils. Brandon Morrison and Queen were, in fact, the only nascent cultivators who hadn't been a part of the secret meetings.
Lex had not noticed when they originally began, but they met so frequently that eventually he noticed it. But the few times he listened in, they were not plotting anything too nefarious. For the most part, they were developing their relationship for when the families felt ready to take back control. Moreover, they were buying special treasures from the devils directly to raise their cultivation levels quickly.