I think this is where the genius of Darkfriends will come in, we know some of those dedicated to the Shadow but not all by far. There could be rulers, nobles and other important people who could turn out to be evil, and there are still some Aes Sedai unaccounted for, not to mention the Asha'man...
She would be 'titular' Queen of Malkier currently, that is Queen in title *history nerd side coming out* I would love to see them reconquer Malkier and be rulers in truth, I think it could happen, with the support of the Tower and all the new discoveries I think after the LB it could be possible.
I think you make a good point about the Forsaken, however I think the circumstances are different. In the AoL there was no Shadow until the Collapse, and nobody really knew what was happening. Nyn has grown up hating the Shadow, she understands what the world is facing better than those who...
Never ever! It would kind of defeat the object of Lan going to fight the Shadow, and his life long war. She would never agree to that. And if she did...could you imagine marital relations after that!? Frosty to say the least!
Interesting theory though.