If they were booked to ORD then ANZ is at least obligated to get them there. If you had other connections on seperate tickets then that’s very bad luck and the risk you take. Other than than it sounds as though ANZ has been reasonable. They did offer economy which obviously wasn’t ideal, but by the sounds of it taking up that offer would have meant arriving in time to not miss the prepaid accomodation. ANZ would have likely provided a generous refund plus a GOGW if they accepted economy.

I have been in these types of situations before, they are awful and you’re at the mercy of the airlines. On a couple of occasions where the airline offered rerouting that didn’t work with where I needed to be by a particular time, I’ve just rebooked on another carrier and route that would have me arrive where I needed to be and in time. I then crossed my fingers that travel insurance would cover the costs. Never had a problem making a claim.