Re: minimum weight
In many countries ex-military craft have the ejector seats removed so a civilian pilot can't eject even if (s)he wanted to (explosives being illegal in a non-military craft, etc).
Yes, but there are also countries where that isn't the case. The UK, for example, permits ex-military aircraft to carry original safety equipment.
There's also the issue that being in the aircraft means that pilots tend to take more care about where it ends up when things go ultimately pear-shaped.
If it's time to eject, that's actually a false premise - the pilot has already lost the ability to decide where the aircraft goes. The problem is that civilian pilots often try to fly through this situation - and invariably make the problem worse.
Indeed there have, but a 1 in 4 chance of permanent disability is still far too high for my liking. There are quite a few pilots who've ejected once and are still in cockpits but very few have ejected twice and been able to resume active duties
I suspect your data might be out of date. I fly with several pilots who have ejected many times - being close to ETPS means that several of my acquaintances are former test pilots. I know no-one who has been rendered disabled by ejection. I know several people who have ejected enough times that your 1-in-4 chance should likely have left them so, so I'm afraid I must disbelieve your statistic.
WRT ejector seats and head clamps: Older ones don't. Newer ones do
Do you have a citation for that? I've seen quite a few in-cockpit shots of Typhoon, and I've yet to see anything that could accomplish that.
In any case the F35 was never designed as an air-combat/air-superiority machine. That's a job for the F22.
Well the original description released for the F-35 was that is was a cost-down F-22. Given that the F-22 cost $150M each, this might still be true - but is is a far inferior aircraft for that price tag.
The F35 is one of the most expensive clusterfucks the USA has ever engaged on and it's going to fuck their economy
It is - but look at what the UK has committed to buy as well. It's not just the US economy that buggered...
 <a href="https://en.wikipedia.org/wiki/Lockheed_Martin_F-35_Lightning_II>Wikipedia</a> reckons the current F-35A costs $98M without engines. Whether this will make it cheaper overall than the F-22 is not a calculation I want to make right now...