In respect to the G-ratings of the F-35, it would do well to remember the lesson of the F-16: the LWF program called for a structural life of 4,000 flight hours, capable of achieving 7.33 g with 80% internal fuel; GD's engineers decided to design the F-16's airframe life for 8,000 hours and for 9-g maneuvers on full internal fuel.
The F/A-18A/B/C/D, as well as the F/A-18E/F are designed to a 7.5G limit - almost identical to the F-35C. The AV-8B is also a 7.5G limit aircraft.
So the F-35C slightly exceeds the USAF specification for the F-16, the F-35B is just about the same or just a hair worse (I seem to remember the F-35 specification is with full fuel, though I might not remember correctly), and the F-35A matches the "excessive" rating that GD decided to build the F-16 to.
The F-35 is designed for a 8,000 hour airframe life - the recent flap over cracks in test F-35B bulkheads occurred in the "second life" portion of the tests, at 9,480 hours - the bulkhead was to be redesigned because the services want a +100% design reserve (16,000 hours before airframe failure).