A "soul" doesn't actually exist on it's own, it's actually just memories of incidents and morals.
I suppose you could also through into a soul "emotions", after all us humans are an emotional breed, and as we continue I'm sure our emotions get more and more complex.
Something that lacks the understanding of right and wrong, and hasn't evolved an emotional being of crying at sadness, being extatically happy when finding love, and angry that they can't complete a game and have to resort to cheating (No one in particular), possibly wouldn't have what you would class as a soul.
Of course a soul you can't exactly point to in the anatomy of a human either, as it's psychological and hypothetically existant, only why your thought processes exist.
You might say "My soul feels alive" when someone dear to you gets close, But in truth they are just stimulating your heart to beat and a whole bunch of chemicals to be produced.
As for the Mortal and Immortality issue of a Artificial intelligence, It's simple, Mortal is defined by having a life expectancy, immortal means to exist forever with no regard for life expectancy.
You could simply ask, would a system would have really lived unless it is mortal?
The only dangers that exist with the creation of artificial intelligence is purely down to how the creators develop it. After all if you treat a dog badly it will bite you, and if you treat it well it want's to be your best friend.
Also the application of an AI is something else to look at, after all the AI might be utilised in Data searchs, or Image manipulation (with AI's it would be possible to create films like "Final Fantasy" within a few months) perhaps your worried about AI's dealing with certain things like for instance "Flying a plane into land", an AI would be less suseptible to being contaminated by a virus or manipulated through a trojan, as a preportion of artificial intelligence would include "Error checking and correction".
Although the system would be no more infalible than ourselves.
It pretty much brings me to something I wrote on another topic,
We are not perfect beings, so what we create will be by default less than perfect, all we can do is strive for perfect.
I suppose you could call that an analysis of perfectionism.