The F35, due to its stealth characteristics, won't have to operate close to the ground very often and thus won't be exposed to birdstrikes to the same degree as non steath fighter/attack aircraft. This significantly reduces the risk associated with operating a single engine fighter.
On the tanker issue, there is no doubt that the tankers will be targeted so, it would not surprise me if the RAAF follows the development of stealthy UAV tankers currently being designed to operate from US Navy carriers. These UAV tankers could eventually refuel from the larger, manned tankers and then sent into higher risk areas in support of F35 missions.