Working with what we've got, I think as a short term solution, Staggs would be able to handle being in the backrow for 80mins. We also have more backline depth and more options to work with to cover Staggs, despite the Hoeter injury.
Carrigan can do a job in the backrow, but then we lose all his work through the middle. I hope we don't do that, especially with Haas out, and Baker starting.
Willison could probably do short stints out wide, but he is possibly more important to us in the front row.
Though, I think we need to give Hetherington time in the backrow to see if he can handle it. I don't see why he couldn't. With Willison and Te Kura in the squad to cover front row, Hetherington probably does not need to exclusively play through the middle anymore. If he can learn to play on an edge, then he is the perfect modern day utility that can play lock, front row, backrow and hooker.