Has the F-35 Lightning II overheating problem been resolved?
As to the first question, it appears as fuel cooling of electronic components and other equipment is integral in the F-35 design, all branches of the armed services will not be able to remedy this problem and it will have to be solved with only fueling the aircraft with cold fuel.  The Air Force has opted to use fuel trucks painted white in order to keep fuel cool while on the ground and it may require refrigeration equipment in fuel tank farms at F-35 bases at an additional cost to the program.

The fuel problems for the F-35 are but one of several hundred faults, shortcomings and outright vulnerabilities with the troubled Joint Strike Fighter program.  While developmental issues are common in new aircraft programs, none so far have been this serious, so numerous and so overbudget without being killed.