LO,
Thanks for coming back, happy to oblige with a reply.
Wing area of the F-35C is driven mainly be the need to recover at high trap weights at an acceptable speed. LO means that many high lift devices are not feasible, so more wing area it is.
The F-35B certainly did have a requirement to be able to conduct a required mission set from a short land base, I think it was about 1200 feet but could well be wrong. That was driving some aspects of the wheel and brake design, I think. The Conops at the time did not envisage getting C-130s in and out, but it's quite possible that they have changed.
Single engine was certainly driven by STOVL, but seen as a desirable move by Pentagon planners. As I've said previously, twin engined aircraft designs have a habit of growing. They were also influenced by the results of a well funded US engine research programme that showed peRformance advantages from a larger single engine.
Hope this helps a little
Engines