Yes, I agree with most of what you say. I have read that book and it is an exciting read.
This question of intelligence is interesting as Hoppe argues the question of what is just only arises because we are capable of argumentation and therefore presumes a minimal level of intellectual capacity. In his discussion of this in “The Economics and Ethics of Private Property” (a wonderful book by the way) he argues that this question doesn’t arise with “a stone or fish” because they are incapable of propositional exchanges. However he doesn’t deal with borderline cases and what the implications of those might be, for example a baby or perhaps someone with a severe mental deficiency?
In relation to the Nature vs Nurture debate I can only relate my personal observations for what they are worth and there I have been surprised by how little a person’s temperament seems to change from birth to adulthood. To use an analogy – people are like trains, they might climb mountains but they always stick to their tracks.