Alicornutopia

Toporting souls is usually done as a swap. Could it be done as a transfer instead? I can't think of many situations where it would be useful, but depending on whether it had similar safety concerns for people who already had cohabiters, there might be some.

I also didn't expect you to have an exact probability, but I was thinking significantly greater than a 50% chance of survival, and that no longer seems like what you had in mind.

Troporting souls is usually done as a transfer, not a swap. A swap would exchange the souledness of two bodies, not put all of the touched soul of one into another. Whether you could swap souls is an interesting question. I'm going to go with no (it overcomplicates the potential logistics, extradiagetically; intradiagetically I have reasons but can't articulate them).