About 1971 there was a proposal to build some VC-10s for China. They were going to be twin engined with RB211s and built at Hurn. The 2 large hangars at weybridge, (Cathedral and Vatican), were to be moved to Hurn and assembled as one.
IIRC the deal was to be 50 VC-10s and 200 One-Elevens.
Then Nixon went and made friends with China and they bought a load of Boeings.
Jhieminga,
Ref. your item 5.
I think you will find that most metal airliner structures are what is now known as "Damage Tolerant " structures. The term "Fail Safe" went out of use after the "Fail Safe" Boeing 707 horizontal stab. failed at Lusaka.
The term "Safe Life" went out of use after the Viscount era I think. We used to re-spar them after so many hours or cycles.
The Design life of airliners is a target not a limitation of hours and cycles. They can carry on indefinitly provided the maintenance, inspection and repair is carried out. There comes a time when it is no longer cost effective to do this.
I don't know about the composite 787 and A350 structures though.
Dixi.