I’d disagree that “non-person: human body, no human soul” isn’t different from “person with human body and human soul”. You yourself are noting that it’s something different than a human body + human soul !!
No, really it isn’t. Using Aquinas’ approach, it has all that animals have (i.e., physical body, vegetative soul, sensitive soul) and nothing that distinguishes a person from an animal (i.e., rational soul). Very literally, it is only an animal, and not a person.