[quote=@Xaltwind]
It's not an exact equivalent, but the concept is the same. The body already existed and was 8 years old when his soul got placed into it. Stands to reason that Morgana and Drasil could prepare vessels in the same way.
[/quote]

They can carry over the souls, but the bodies are dead/dying so they get left behind. And they get new bodies based on their desires.