I am really interested in this concept. Before coming to this forum, it never occurred to me before to think that some people might not have souls. Or more specifically that a human body could not be associated with a soul. This was always a root assumption for me, unexamined and unquestioned. I always like to turn assumptions inside out and consider other possibilities, so it's wonderful to think about this.
I think what I posted here gives an interesting description (accurate or not) of how the original OPs became individuated souls.
I am wondering how this concept relates to the shamanic idea of soul loss. Could some apparent OPs be people who were born with a soul that decided to leave the body because of trauma, or unacceptable life circumstances? Does a human body lacking the strong presence of a soul automatically revert to the hive-mind?
If a damaged body is brought back to life through medical heroics, and the soul does not wish to return to the body, could this person turn into a soulless OP? And what about walk-ins - can a soul enter an OP's body?
Is there a fundamental difference in the physiology of a souled human and an OP that would prevent an OP from becoming souled, or vice versa? If so is it basically unalterable, or can it be switched on or off through genetic manipulation?
Could a souled person be "deactivated" into an OP via abductions, trauma-based mind control, or medical experimentation? Can drugs, psychiatric or illegal, destroy the soul's connection with the body, thereby converting the person into an OP?
What I can really relate to and agree with emphatically is the idea of soul emulation. I have witnessed this and experienced other people doing this to me personally countless times. I would take it a step further and say that the ultimate goal of this is not simply to simulate having a soul. It is to actually emulate another person's soul identity, so that the emulator would actually be perceived by others as having that person's individual soul qualities. This can involve a strategy of slandering the person's character, and/or driving that person to behavior that is contrary to the true nature of their own soul.
Celebrity impersonators are soul emulators who may or may not be OPs. Those who are used extensively as doubles or replacements for celebrities in the public eye are "stealing" the soul identity. They are diverting the concentration of the masses upon that admired soul onto a simulated version of that person. Those soul qualities are perceived as belonging to someone else who may have a very different nature. The result is a deeper collective confusion about who is who, and what is what, and a dissociation from the physical senses. Soulless may be perceived as ensouled, and the physical characteristics that distinguish souls are no longer recognized as unique. What looks alike and sounds alike is perceived by the masses as being the same identity, because the soul that animates the body is simply not perceived or recognized.
On the subject of animals, I don't believe that animal souls are lower or necessarily different than human souls. I believe that they can be vessels for "human" souls, if a soul wishes to have that experience. I feel strongly that domesticated cats in particular were perhaps genetically modified especially for that purpose. A soul who wishes to be with a beloved soulmate may choose to enter that person's life as an animal or bird companion.
I recognize very particular characteristics of some of my soulmates in my cats, right down to them even having phsyical markings that suggest who they are! One for instance has the look of a gray beard under his chin, very similar to the one he had in one of his human lives. As a kitten he tried mightily to play the piano, but when he found his paws would not work as well as human hands, sadly he gave up. Another of my babies has an unusual "singing" voice eerily similar to her human counterpart. But what I recognize most is the feeling of their own unique soul vibrations, these ring out crystal clear beyond their "catness".
A soul may choose to incarnate as an animal to learn about the spirit and qualities of that animal consciousness. This can be motivated by curiousity, a desire to develop qualities of character, or the need to serve penance for mistreating that animal in a human life. On that note, it seems to me that many souls still have a lot to learn about being cows, chickens, and sheep.