I agree that Queenstown will be hugely problematic to this schedule. When I used to fly in there in a non RNP -AR capable aircraft we would often divert. I remember at one stage diverting three days in a row.
If Queenstown wasn't part of the mix and there were two aircraft it would seem viable. Whatever they do they have to stay away from the fracas on the routes contested by Jetstar.
Good luck to them. I'd love to see them succeed.