That Rand will actually support the Seanchan's attack of the WT, after they make their alliance. He will beleive that he has to liberate the WT from the Shadow and free Egwene, because IMO he will eventually learn from Semirhage that Mesaana & the BA basically rule the WT and that Egwene is a prisoner there. Normally Rand should also already know from Narishma that Aran'gar (the female Forsaken who channeled saidin at the Cleansing) lived among the Rebels and probably manipulated them as well.

This explains how the Seanchan will know about Egwene beforehand as the Dreams indicate, and why Egwene will be angry about Rand, when she faces him the next time.

Mat is Prince of the Ravens, but most likely won't be involved in the Seanchan attack, because he has to rescue Moiraine.