In relation to the economic cost of point 3, the difference between business and economy
I suspect Qantas may have already provided an economic cost for this issue. @papeto mentioned that Qantas asked for the refunded points to be return back to Qantas.
I understand that the principle here is that if Qantas is paying for the new economy fare then they need to have retained the original payment in the form of the points.
However, it seems to me that those points represent the difference between what was booked and the alternative of the economy airfare. These are in fact the cost of having to fly economy instead of business.
Yes, I'm making a pretty vague argument here, but I'm sure a good lawyer could finese it into something useful.
Has it been clarified in this thread exactly how many points moved in which direction? I agree that on a purely economic perspective, if @papeto was refunded all of his points for the non-flown J itinerary, it makes sense that he might need to repay points equivalent to an economy-class booking, in exchange for his costs for that booking to be reimbursed in cash. This would make him whole in relation to the economy-class itinerary that was actually flown, which he did get the benefit of (regardless of the delay matter).