Xingke will probably not be privy to the reason why the Knights ousted Zero. And even if he is, he probably won't believe it, since he feels he got a good grasp of Zero's character in the episode where Zero refused to marry the Tanzi off to a Japanese dude.
Toudou is tricky. He has enough background info on Lelouch and Suzaku to be able to understand the true context of the conversation that will be leaked, as well as be able to recognized any discrepancies caused by Schnizel spinning things his way. But he has put forth the notion of betraying Zero in the past and had a close subordinate of his die on him recently.
Toudou is the only competent commander I can see staying on with the Knights, and even he might not stay.