I can't see that "story" implies fiction." If I said of someone "He told me his story", I couldn't see that implication at all. "My mother once told me the story of how she met my father".

I suppose you could say that telling a story implies an element of shaping how you present the facts. And in the case of a true story, one of the reasons you are doing that is to convey the truth more effectively.

I agree about "splendid battle" - there's no such thing - but when you're writing a song in a hurry, you stick in a word that fits the sound, and it might not in the end be the best word. That's what I meant about the way that the oral process can improve songs over time.

And in that song, if you take out "splendid" there's nothing directly saying "aren't they brave", it's all implied.

Well, maybe that line
The stakes are death or duty, no man has answered No! has a touch of it - and I'd probably change that too. Maybe something like
Though death is out there on the sea, no man has answered "No"

I think making changes like that is just trying to do the kind of thing that the oral process would have done, if the song had got into the way of being sung by people with memories that failed, and altered the words round a bit.