After carefully reading the entire original post, my first thought was that Aurane tells Cersei about Loras and the fall of Dragonstone. How else could she receive this information? Via raven, of course. And who controls the ravens in the Red Keep? Pycelle. And Cersei has been an a-hole to him recently. Furthermore, we know that at the end of aFfC, Pycelle (along with Harys Swyft) has sent a raven to Kevan to assume the regency. I think Pycelle wanted to take Cersei down. Not necessarily the Lannisters, but Cersei. If he was approached by a member of the Tyrell crew with this plan, I think he would agree to it. All he needs to agree to do is withhold any information coming from Dragonstone. He is not an ACTIVE member of the conspiracy, merely passive. Aurane steps in, fills Cersei full of this false Loras info, and Pycelle doesn't need to know much of, or participate in, the grander scheme. If it fails and Cersei is not imprisoned/removed from power, he can merely claim he never received a raven, which is highly plausible. His hands are virtually clean. He might also have been supplying Moon Tea to Marge, for someone else. He is, of course, never allowed to finish his sentence while talking to Cersei. I don't know, there definitely is something going on in the Tyrell camp; Taena is a spy. And the whole Loras/Dragonstone thing too easily fell into Cersei's fingers. And whenever something easily falls into her designs, it would be safe to assume it's because someone else designed it. Anyway, I like this theory. It might not be right in every aspect, but there is definitely some truth in it.