Are you asking if you can get a villager if they're moving in someone's dream town...? I've never actually seen a dream town that had a villager moving, but my guess would be no.... I mean considering the fact that nothing you do in a dream town affects their town, I imagine asking a moving villager wouldnt have any effect in the "real world" either.... there's also the fact that who knows how long ago they updated the dream, the moving villager may have moved already in real time...