Still there.
I think (based on how I interpret King's concepts of other worlds) there are Keystone People, just as there are Keystone worlds.
In the other worlds, other versions of the keystone person exist. But they are essentially shades of the keystone self. What I mean by that is, that if they are killed they simply die, whereas the keystone self - upon death - can travel into/inhabit the life of any of it's other selves. This explains the Jake that Roland, Suze and Eddie draw and also
I think normally the keystone self forgets it's previous life