For me Valeris was too obvious a role to be a co-conspirator. She reminded me of MacDuff in 'Conundrum' - you have a new person suddenly part of the family and when things get weird who do you think might be the one responsible. I think Saavik would have been more appropriate since she was already known to everyone and part of the familiar crew. Chekov going dark would have been a real surprise, but I like his character and it would be a shame to see that career end that way.
I do think Chang was on board Kronos One- part of the entire ruse is to foment war with both sides, otherwise he could have just shot Gorkon on the way there and blew up the Enterprise as they were arriving. He needed the Klingon crew to see what Kirk had supposedly done. While the crew of the BoP was entirely with the plan, aside from Chang I do not think anybody on Gorkon's ship was- they were loyal to him and served on his personal flagship. There would be no reason for Change to sneak off to the BoP just to fire two torpedoes when had been planned- it would be more important to have him on board the main ship in his position to deal with the Enterprise and make sure 'justice' was served.
I think the plan was for the two ships to battle and if it looked like the Enterprise might win the cloaked BoP could get in a couple of shots which would ensure victory for the Klingons. Cartwright would make sure the loss of the Enterprise along with the Klingons declaring war to avenge their leader would get the war started.
I do think Chang was on board Kronos One- part of the entire ruse is to foment war with both sides, otherwise he could have just shot Gorkon on the way there and blew up the Enterprise as they were arriving. He needed the Klingon crew to see what Kirk had supposedly done. While the crew of the BoP was entirely with the plan, aside from Chang I do not think anybody on Gorkon's ship was- they were loyal to him and served on his personal flagship. There would be no reason for Change to sneak off to the BoP just to fire two torpedoes when had been planned- it would be more important to have him on board the main ship in his position to deal with the Enterprise and make sure 'justice' was served.
I think the plan was for the two ships to battle and if it looked like the Enterprise might win the cloaked BoP could get in a couple of shots which would ensure victory for the Klingons. Cartwright would make sure the loss of the Enterprise along with the Klingons declaring war to avenge their leader would get the war started.