The sul'dam can compel her to make the weave with the a'dam (as Renna did to Egwene), and the matter of identifying her is irrelevant as there are more than enough sul'dam available to work on all the captives at once.

The Seanchan as good as got Travelling now.

For the rest, it's more a matter of how long it will take them to adapt their tactics to use it in battle, but they have their fears of a counterstrike by Rand/WT to motivate them to move fast (they were aware of this when they decided to raid the Tower, so they probably have plans in the works for the aftermath).

Personally, I think Brandon "cheated" a little to be able to divide the book. Originally, Yulan's plan involved two different maps, the one of Tar Valon being the only one revealed in KOD, the second one being left mysterious. I suspect originally there was a plan to raid the BT (or Logain,s forces at the Illian border) after the WT in Yulan's strategy, but Brandon decided to have the Seanchan completely overlook the Asha'man in TGS (despite being well aware of the threat, which they faced in the Venir range as well as at Anath's capture, and they were involved at Malden). It was quite a plot hole for Yulan to totally overlook the Asha'man and focus only on the Aes Sedai. I think it's the result of excising a story line from the whole that progressed well when all story lines ran in parallel but foreshadowed events in ToM too much after the book got divided. I think Brandon decided striking at the Asha'man would now come second. I would not be surprised there are more Tuon/Seanchan chapters set before the raid on TV in ToM, developping what else they were planning.