I said that the progressive form was unlikely. After thinking more about it, I should perhaps have said 'less likely, in my opinion'.
She had been fighting for 8 years before reaching a settlement with....
I don't understand why this would mean the fight went on after her death. Like you said, it would emphasise the duration? I think that's the knot in my brain here...That is one common use of the form, but it is not the only use of it. Depending on the verb and the context, the non-progressive form can also often be used for this idea. As I said in post #2, there is no simple answer to this. In post #7, I attempted, not very successfully, to suggest when one form might be more likely than another. I should have remembered my own words, "Some course books and elementary grammars can sometimes give the impression that only one form is possible in any give situation. This is not true."I remember from school that the past perfect progressive (she had been fighting) is used to express that something had started earlier in the past and continued happening until a new event set in.
"He had been travelling for 3 months when he ran out of money"
The fact is that there are no hard and fast rules here. There are situations in which one form is more likely than any other for most native speakers. There are situations when one form is unlikely for most native speakers. There are also situations when two or more forms are equally likely. There are few absolutes here.
It seems to me that you have a pretty good idea of how we use the various tenses and aspects.If you stick to what you know, and accept that native speakers may at times say things that seem 'wrong' to you, you will not make any serious mistakes. Indeed, in my opinion, you will usually produce forms that will seem natural to native speakers.