The metaphysics of original sin

I'm going to revisit the issue of whether original sin is fair. It's a topic I've discussed from various angles. For instance. 

https://triablogue.blogspot.com/2015/04/vicarious-responsibility.html

1. In the Genesis narrative (Gen 2-3), as I construe it, humans are naturally mortal but with a potential for immortality, contingent on access to the tree of life. When Adam and Eve are expelled from the Garden, they lose their shot at immortality. And that's a lost opportunity for their posterity as well. To be born outside the Garden is to be consigned to morality, as the default state of humans, absent the tree of life. 

For Adam and Eve, the lost opportunity of immortality is punitive. But is it punitive for their posterity, or is that merely a side-effect of what their ancestors did?

To take a comparison, suppose a businessman becomes rich through hard work, but squanders his fortune through compulsive gambling. As a result, his kids inherit nothing. But they aren't being punished for their father's gambling debts.

Now, a common objection is that it's unfair for humans to suffer the dire consequences of what was done by a second party (Adam and Eve), without their consent. But whether that's unfair depends on whether humans are entitled to immortality. 

To revert to my comparison, it's not a miscarriage of justice if the kids of the impoverished rich man inherit nothing. They didn't earn the money. It wasn't theirs to lose.

The question is whether the imputation of Adam's guilt is directly punitive, or more in the nature of a hereditary liability, for something humans never had a claim on in the first place.

Likewise, the question of whether original sin is damnatory, or whether that's reserved for actual sin.

2. Is it fair to be born with a sin nature? Not only do kids inherit physical traits from their parents, they inherit psychological traits from their parents. And I think that's evidence for traducianism. I'm a Cartesian dualist traducian.

If alcoholism runs in your family, you may have a chemical or genetic predisposition to alcoholism. That's unfair, but you wouldn't even exist if the deck was reshuffled. 

Likewise, you might inherit a bad psychological trait. Suppose your dad has a short temper, which you inherit. You might say that's unfair, but you wouldn't even exist without the father you had. That's part of your psychological makeup, and your origination depends on it. Some psychological traits can be modified or eradicated, but that's after the fact. They can't be eradicated in advance without eliminating you!