Because of Kyle's pitiful performance during his previous Ordeal, he was the only one who didn't buy a Floating Island with the others. Instead, he had decided on its future location.
For Tim and Esya, although they could afford a basic Floating Island, they didn't have enough resources to develop it. Just the terraforming, the anti-radiation force field and stellar objects, and a breathable atmosphere and temperature would cost them too much Aether and leave them in a precarious situation.
That's why after buying and placing their Floating Islands, they planned to leave them vacant for the time being, until their Aether Storage reserves were strong enough.
Consequently, apart from Jake who intended to go to his Floating Island alone, Tim and Kyle had chosen to accompany Will, while Esya would live with her sister. Only Sarah had chosen to go alone. In any case, their Islands would be next door to each other.
