CONTAINS SPOILERS

It's possible to send your new team of Miis back to a previous land. If you view the image above, you can see that my Realm of the Fae Mii is in Neksdor, the previous area. This is proven by the low level cleric gear and the Youngest Fab Fairy NPC by her side. This strategy is effective due to the fact that enemies' strength increases as you progress further in each land.