Suggests adding a new location, like a "Mii Hotel," where Miis could stay as temporary residents or travelers. Players could then choose to move these temporary Miis into the main apartment when space becomes available, similar to how Mii children are handled.
For some reason in my dreams, I thought there was another apartment near the park and Mii News and I forgot what it was called(maybe Mii Hotel or something), but unlike the normal apartment, the Miis in there were only temporary residents or travelers to stay there until there is an empty space in the main apartment(if a Mii gets deleted) and the player can choose to have the temporary resident move in or get sent away, kinda like when you have the exact same choice when a Mii child grows up.