If Verrin knew that a massive army of shadowspawn was about to attack Andor, chances are she was aware of a plot to attack Perrin with an army+channellers. She knew a fair bit about portal stones too. I'd guess there are at least one or two darkfriends in the whitecloak army as well.
Chances...
Hell yeah, Egwene standing in a gap in the walls, blazing with the light of Sadir was bright as the sun, the look of wrath in her eyes, raken swirling overhead...
That would be epic.