I’m a spiritual kin, so I don’t know how to reconcile factkin with living people. Wouldn’t the living person’s soul be connected with their own soul from other universes?

Not necessarily. Personally, I consider most different universe versions of a person different people soul-wise. For instance I don’t think I share a soul with every version of Ken Ichijuoji, just the specific version of Ken Ichijouji that I was/am. Other Ken’s have their own souls.

The reason I say most is because there are certainly some people/characters who share one soul across multiple instances of themselves across universes.