Hello Dawne,
Thanks for sharing your inputs. Yes, the management of surnames is not precisely obvious in these cases.
I remember my parents had "visit cards" about 35 years ago where my Mom was named "Carmen Vazquez de Pipaon", following my Father's name and because of it (She was only "Carmen Vazquez"), I understand it was a kind of formal way to express that she was "Pipaon's wife" (with a sense of property as you mentioned) and I would say that at least in Spain this habit is now completely obsolete. By the way I have never seen here anything similar in the opposite direction, like "changing" the husband's name due to marrying, as you mentioned.
Nonetheless, this did not mean that she had taken by any means "Vazquez de Pipaon" or "Pipaon" at all as her last name or part of it. This could be a misinterpretation by whoever could have read one of those old visit cards if they would not know the context.
Her "first surname" was during her whole life, after and before marriage, "Vazquez", and I would say that the formal way "Vazquez de Pipaon" was just something you could read only in visit cards, never in any "real" document or anywhere else. It would have been absurd and "illegal" because that was not her surname.
Of course this may have changed across time and space (America vs. Spain), and the examples you added have the difference that they happened in the US if I understood correctly, I mean in a total or partial English speaking environment, so maybe the way to manage surnames might have been different there.
The point here and now in Spain is, we don't have anything we can refer to as a "Family name", I mean families don't have a "name", people do. So you might refer to a family informally as "Los Lopez Mendieta" concatenating husband's and wife's surnames, and that is in fact quite common, that sort of "Family name" would match that family children's first and second surnames, but none of the parents is really a "Lopez Mendieta", the Father will be Lopez-Whatever and the Mother Mendieta-Whatever-Else. Of course I am simplifying it to the classic family model formed by Father+Mother+children. But even focused on it, this is why I say it is not really a "Family name", because not all members of that family, especially the ones who formed it, have that name. In an official document, for example, you will never be asked about family names, only persons' names, one by one.
We sometimes use only our "first surname" and sometimes use both "first and second surnames", but they are two different surnames, not a composite one. That is a different thing that also can happen, especially when analyzing older records for genealogy purposes.
From "third surname" onwards, it is only used to show "how many of your surnames are you able to say...", but never used in real life.
Thanks again,
Aitor Pipaon Vazquez (or just "Aitor Pipaon").-