maybe it will be cheap enough so that they don't need a rent-a-car C-17 type arrangement
RAF owns their C-17s now. It's no longer a lease arrangement.
I also suspect that many of the likely customers aren't that interested in actual utilisation rates - they just need to have some aircraft around to replace their earlier Hercules variants - actual useage will be low
Maybe, maybe not. This is much is certain: the buyers of the C-17 have ALL bought the Boeing support package, even the ones who only bought two.