Yes, LibreOffice Writer is very much a stylesheet-based word processor. After you open your document, examine the Navigator tab in its sidebar (View ▸ Navigator if the sidebar is closed). What you want to see is an indented list of headings that matches your draft folder outline. If you’ve got that, then your numbered heading styles are set up right.
You’ll want at least RTF for it, but ODT may work better. It can’t read RTFD.
My apols, again, Ioa: do I understand correctly that Scrivener has two ways to create and use Headings? One of them (the one I have used up to now) goes in the text itself - to indicate paragraph heads for clarity of reading only? And that Scrivener can also apply Headings specifically during the Compile?
Those are two optional ways of doing so, yes. There are actually more ways than two, but those two are all that matter here.
However it wouldn’t be right to say one is only for this and the other is only for that. Again, this post explains that. The final word processing document does not care one bit how or where the hierarchical headings came from, that’s a distinction that only exists in Scrivener.
Headed paragraphs, or non-hierarchical headings, should just use style names that do not match the “Heading #” naming scheme in Scrivener. That’s all there is to it—again such can come from anywhere we please it to, not just one place or another.
If both, wouldn’t I be wise not to create (?) Heading styles whose numbering overlaps: that is, use Heading 1, Heading 2 in the text for paragraph clarity; and Heading 3, 4, 5, 6 (?) for the structure/compiler levels?
I don’t follow what this is driving toward, so it’s hard to say if that would be a good idea or not. Reading that literally though, that would feel a bit awkward to me. More typically I would expect to see lower, or more minor headings (like “Tetrachords”) in the text, and higher, or more major headings (like “Part I”) in the binder. I guess you could do things the other way around, but like I say, that sounds really awkward. Your primary book divisions like parts and chapters would only be found inside text files, but really super minor headings would be split out in the outline?
You absolutely could do that if you wanted to. There no rules about any of this. To circle back to what was said before: all the matters is the output. How it got that way is immaterial to the word processor (or Scrivener’s Split & Import routine, for the sake of this one very narrow use of that structure).
What could I use instead: perhaps a Text Heading 0? Or Text Heading 1 and bump existing Text Heading 1 to 2, and 2 to 3?
There is no heading 0, “1” is at the top. Whatever is at the top should be heading 1, in an absolute fashion. It doesn’t start over in each document (relative fashion). If your book has parts it will always use Heading 1 and nothing else would, unless it is a part.
From your screenshot, I would guess what is performing the function of the text styled “Title” should really be “Heading 2”, but for all I know the “Chord” folder this file is nested within is purely for keeping things straight (it isn’t meant to compile), and the items beneath it are actually meant to be chapters, and thus if there are no parts in this book, chapters are the highest level and thus what you are using “Title” for should be “Heading 1”.
It’s obvious that Scrivener is so rich in this area that there might - for me - be a wood/trees issue…
To an extent I would agree, but it’s really more that word processors and their document formats are super rich, and have rules that are supposed to be followed to make them well-formed. Scrivener by comparison is actually pretty simplistic when it comes to that stuff (it is richer in the toolkit used to construct text, overall I would say, while word processors are pretty simplistic: just jam it all into one massive scroll view). For what we are mainly discussing though, Scrivener only addresses a tiny fraction of what these tools do, but if you do want it to create a well-formed document you have to set it up right, and knowing how to do that is one part Scrivener know-how and three parts knowing what the product even needs to be in the first place.
And the ‘structure Headings’ (?) inserted by Scrivener specifically for Compiling disappear?
Only if you tick the option I referred to in my instructions.
At any rate it sounds like you are on the right track with your proposed experimental project. Everything I said about experimentation being safe is only more so if you’re playing with a project that exists only for that purpose. We all have different learning styles, but for me anyway, at a certain point any form of instruction stops making sense until I get in there and play with it.