Libre office can read any Word file directly, so if you have an older document (even .DOC) in which you had set up styles you like, once it is opened by LO then those styles are incorporated. Alternatively, you can manually tweak LO's existing styles to match their nearest Word equivalents. I go back and forth between programs all the time. (Though I've read, but have not yet experienced, that some formatting issues can result by doing this).
There are some oddities: for example, if you often use em dashes to set off part of a sentence, LO will properly put the first em dash in when you type two regular dashes together, but insists on keeping two regular dashes for the second instance, and this can't even be fixed with autocorrect.
For both ebook and print , it doesn't matter what styles you use, since you can define styles any way you want (or as needed to match publisher requirements, such as margins and gutters). What's important is to use the styles in the first place, and of course how 'clean' the html is during the ebook creation process.
