RR_NDB,
I also agree 100% with your post#81.
As you say: A third case is inconceivable - so right and BOEING knows that!
Therefore I think they will have to go back to the "old" battery technology as the best option for getting this very important project on track again.
In any case before the type will be allowed to fly again, BOEING "must demonstrate to the FAA that the battery system is safe" - not an easy job with the current system, bearing in mind the many known causes of Lithium-ion battery failures.