We know Cyndane and Moghedien both spent some efforts to try to get Perrin and Mat killed.

I've always suspected Lanfear tampered with Masema.

I don't really see who else but Lanfear would conceive in TDR that sending "divine visions" to a madman like Masema so he built for Rand a religious following of utter fanatics was a good notion. None but Lanfear had this notion that she would control Rand sooner than later, and rule with him under the DO. So in the end, Masema's followers would be Rand's, and thus Lanfear's. She merely had to add worship of herself to the mix, down the line.

Also, this was all accomplished through dreams, and that's one of Lanfear's MO.

I think Masema is just one of her avorted projects. She's started it, and moved on. When Moridin ordered the Chosen to get Perrin and Mat killed, Cyndane tried to use Masema again, and it worked.. but his chosen pawn failed.

The attempt in Amadicia and Masema were the only attemps made on Perrin, so if Graendal is right that Cyndane and Moghedien were trying to accomplish those orders, it has to be one or the other who's behind it. Cyndane appearing as a divine version of Rand makes a lot more sense than Moghedien doing it. It has the style of Lanfear all over it, IMO.