Your points about the defining characteristic and about the conflation of concept and characteristic were well said.
I would add that the engine might be out of the automobile for repair, Yet it remains an automobile. Just as a man in a coma is still a man. Rights are derived from human nature (all men) and therefore the existence of the conditions that give rise to rights do not need to be re-established for each instance of man. (i.e., We do not need to say, "This is a man, and this man is exercising a rational faculty, therefore this man has rights.")
And for that reason, all who are humans have rights even if they, as individuals, can't exercise choice (babies, people in comas, when one is asleep, etc.)