I think the most interesting thing about Peace Talks is which Senior Council members and other high-ranking wizards are sent to the talks and which stay behind.
McCoy
Listens to Wind
Liberty
Christos*
Stays Behind: Merlin, Mai
Outer Gates: Rashid
Of Harry's known supporters, only Rashid is missing. This, of course, is unsurprising since Rashid does not participate that actively in Senior Council shenanigans.
In addition, all of Harry's friends/supporters among the New Guard Wardens are sent -- Chandler, Rameriz, Yuki, Wild Bill.
One is an accident, twice is a coincidence, three times is enemy action. EVERY Harry supporter on the Senior Council is unable to attend the meeting? Every. Last. One. All of Harry's friends among the Wardens save Ramirez and Lucio are unable to attend the meeting. Every. Last. One.
What's the result. We know from Proven Guilty that Merlin holds ALL their proxies. Merlin votes for McCoy, Listens to Wind, Liberty and Rashid (who undoubtedly is busy at the Gates) to expel Harry -- at least. He may well have voted for Christos as well. Ramirez, whose faith in Harry is already shaken, is permanently (seemingly) divided from Harry by being manipulated by Langtry in being the messenger. Langtry knows Harry well enough to know that Harry would "shoot" the messenger, given his persistent oppositional defiance disorder. Langtry has long wanted Ramirez on "team Langtry" to counterbalance Harry's popularity among the younger wizards.
Seems like he succeeded. Bigly.
* Christos may actually be a Harry supporter. Yes, he benefited from Fortier's death; yes, he didn't like Harry interfering with his "diplomacy" in changes; yes, Harry suspects him of being on the Black Council. But, his inclusion on the "away Team" means that the Merlin may have wanted him out of the way for his Harry vote scheme.