Great set of options, PM. The baby's ugly, but it's your baby now, so cough up the $10 billion in child support like a good chap.
What AFs need to do is evaluate their real options. Staying with the F-35 will leave the US, UK and some others with a mix of -35s and "classic" fighters - that is to say, not stealthy in the 22/35 sense but with signature reduction measures - through the 2020s. The overall coalition force will still be a mix because the US will still be replacing teen-series jets in 2037.
I don't think any adversary will be anything like all-LO before 2030 (although that's a long time to make any predictions).
Regardless of the 4gen/5gen sloganeering by LMT and its cheerleaders, current operational fighter types will have to be kept relevant through the 2020s, as fighters have always evolved - new sensors and weapons. But that will be difficult unless F-35 turns out to be much easier and cheaper to upgrade than the F-22, which has the same kind of architecture (central avionics processing and unique, complex apertures).
And if the F-35 is unaffordable in the required numbers, it isn't an option anyway.... as the F-22 was not, even for the US.