A thought on external tanks, if the F-35 makes 1000nm+ straight line on internals (and I have heard it is considerably more) external tanks only really make sense for ferry flying. That means going high and carrying 8000lb of fuel in the tanks up to 30K'. In itself that takes a lot of fuel. Now consider the drag of 2 x 500gal tanks, and the fuel required to overcome that drag, for the climb to 30K' and for the 1000nm+ where the jugs are not required. Adding all that up means the additional range from the tanks is not nearly as far as most would assume - certainly much less than 8000/cruise fuel flow * cruise speed. Even with 'coke bottle' area ruled low drag tanks the additional range for an F-35 type aircraft might only be 100 or 200nm.
Is it worth spending the money to develop and test the tanks for such a small increase in ferry range? I'm assuming the jet has some wet pylons, so tanks could be fitted at some point in the future, but I guess for the current roles there is no real justification.
On the spares support front, it would be beneficial to understand how the F-35 'autonomic logistics' actually system works before deciding if multiple operating bases would be a benefit or impediment.
Phil