prOOne,
The question of who owns the Voyager fleet in not a simple one to answer. Some of the fleet will be available to thje RAF to meet daily tasking but some will be used by Air Tanker to meet purely civilian tasks. Whether those aircraft would be instantly available to the RAF if there was a sudden increase in tasking is debatable. Those aircraft on civilian tasks would certainly not be crewed or serviced by RAF personnel.
As far as equipment is concerned, only a proportion of the fleet will be 3 point Tankers, the rest will only have wing pods which may be removed for civilian operations. I suspect there are still some questions to be solved before the aircraft is in full service, welcome as it will be.