Night Elves are Kalimdor to me. I would hate for them to end up in the Eastern Kingdoms, but I would be okay if maybe they built a new capital in Zin-Azshari after Azshara is killed.
Forsaken I think would be okay resettling to the ruins of Theramoore. Dustwallow fits the undead motiff really well and it perhaps it could be explained that the Forsaken replenish some of their losses with the fallen from Theramoore. That or have them resettle in Northrend