Interestingly, Linus, before I posted my
You’re right. 
,
I had drafted a corrective post similar to yours, but then decided that you were right after all, since Feser continues:
The condition was the obedience of our first parents. Yet they did not obey. And of course, that is the point of the account of their eating of the fruit of the tree of knowledge. It wasn’t fruit per se that was important, but rather the will to rebel against the Creator. (Recall Augustine’s youthful theft of the pears, where what was attractive about the theft was the fact that it was forbidden, not the fact that he got some pears out of it.) The penalty was the loss of the supernatural gifts they had been given and that their descendants would have been given, and a fall back into their merely natural state, with all its limitations. In particular, it was a loss of all the helps that would effectively have removed those limitations – and worst of all, loss of the beatific vision.
So that suggests that Feser thought they had already received all those benefits, but then they lost them.
Yet then he continues further, and that changes things back to your final analysis:
In short, the penalty of original sin was a privation, not a positive harm inflicted on human beings but rather the absence of a benefit they never had a right to or strict need for in the first place but
would have received anyway had they not disobeyed. And it wasn’t the prospect of pitchforks and hellfire that Adam’s descendents had to look forward to because of what Adam did, but rather the privation of this supernatural gift. What is essential to Hell is the loss of the beatific vision, and while Hell can certainly also involve more than that (including the pains of sense) the standard view is that it does so only for those guilty of actual sin, and not those (such as infants who die without baptism) who merely suffer the penalty of original sin, without ever having committed actual sin.
Note the emphasized part. Here it seems that Feser really wanted to say they didn’t actually receive these benefits (“would have received…had they not…”).
That suggests that Fester is doctrinally correct, but that indeed, as you point out, he could have worded things much better in order to avoid unnecessary confusion.
So yes, I think we are in agreement.