You want a complex Egweane and Lanfear relationship? Here it is! Mesanna either can channel and is hiding it, or uses the TP (like Lanfear). She realizes that she can't control Rand and everyone thinks she dead, but we all know that's not true. She was the Fat woman in the Three-Fold Land. So we know she can appear as anyone. Lanfear is getting close to the "New" White Tower so she can spy/manipulate without revealing her hand. Also through Egweane, she can get her hooks into Rand. Lanfear, not just Fatal Attraction, but a master at the Great Game. Sorry, I have little proof, but Lanfear is a more logical choice.