So what exactly are you expecting to go bad here? Tzeench himself whispers in the ear of a random Kurgan that we are not what we seem? I think he is a might busy building schemes and tearing them down again for what.
Tzeentch whispers contradictory instructions in the ears of ten Kurgan shamans simultaneously.
"There's an Imperial Magister coming, kill her for my favor."
"There's an Ice Witch coming dressed as an Imperial Magister, capture and ransom her to Kislev."
"There's a Chaos Champion coming pretending to be an Ice Witch dressed as an Imperial Magister, do as she asks of you."
"There's a pair of Dwarf Rangers coming, sitting one on top of the other while riding so they look like a Chaos Champion, pretending to be an Ice Witch, dressed as an Imperial Magister, warn the Chaos Dwarfs about them."
"There's a Changeling coming who has taken the form of a pair of Dwarf Rangers sitting on top of each other [...] dressed as an Imperial Magister, and the next four shamans over are all misinformed about the situation. Take advantage of their ignorance."
"There's an Arabyan magician who has made a pact with a Changeling who has taken the form of [...] dressed as an Imperial Magister, and I want you to make him think the Empire has designs on Araby."
"There's an Arabyan sultan who's hired a magician to make a pact with a Changeling [...] dressed as an Imperial Magister. Show his messenger the utmost favor and stall her for as long as you can."
"There's a necromancer puppeting the corpse of an Arabyan sultan who's hired a magician [...] dressed as an Imperial Magister. I want you to expose her so that my demon plots are blamed on necromancers for a while."
"There's a vampire who's taught a necromancer to puppet the corpse of an Arabyan sultan [...] dressed as an Imperial Magister. Avoid her at all costs personally, but try to lure your rivals into this vampire-versus-me plot."
[Entry ten is Tzeentch rambling for so long that the shaman loses track and decides to try reading the omens again tomorrow, maybe they'll be clearer.]
If some of the shamans compare notes, this too is JUST AS PLANNED, Tzeentch will leave them uncertain and unable to determine who relative to each other is "he knows a layer more than me about this complicated Tzeentch Plot" or "he's making things up to throw me off, surely it wouldn't be that complicated."