You did it! We figured this one out! It is a truth universally acknowledged (by me for certain) that the Bitchery pretty much knows everything, and really, it's true. Scroll down to see the solution for this HaBO - and many thanks!

This HaBO request is from Di, who is in search of a gothic novel or an older novel with supernatural elements:
I read a series of books that were gothic/supernatural in the 1970’s or early 1980’s.
The heroine (Amanda?) of the books is trying to get control of the family business (shipping/shipbuilding, maybe) and she blackmails a local man into marrying her. I believe she threatened his family and their own business — so he married her. They had one or more kids. She died within the first couple of books and haunted future generations of the family. Or inhabited them and made them make morally questionable decisions. In my memory they were of the gothic genre, but it was along time ago, and the covers somewhat reflected that. I believe it took place in the eastern United States.
I remember them because of my own nascent realization that what the heroine did was bad, but I could understand that she was a woman being penalized for not being a son/man by her father. Which is so not right. I wish I could remember more, but I’m afraid this all.
Is this description familiar for any creepy series from a few decades ago?

I can’t believe I know one of these! I believe the series is called Saga of the Phenwick Women by Katheryn Kimbrough. All the titles are women’s names and the first is called Augusta the First. It lasted for forty books mainly in the 70s! I picked up a few in used bookstores. They are interesting for mixing romance with the unpredictability of the gothic genres – some had bummer endings or revealed the seemingly happy couple of a prior book now disliked each other.
I just did a Google image search for this series and CAN NOT BELIEVE I never read any of them. The covers are so perfectly 70s/80s. I love them so much!
This is Di. Thanks dr opossum, it’s the correct series, though not quite as I remembered.
OMG, I remember seeing these around when I was a kid. Those images are great! My favorite title: Peggy: The Concerned.
Although things don’t look good for Olivia: The Tormented or Isabelle: The Frantic
Sincerely,
MirandaB: The Drowsy
Back in the day, I eagerly grabbed any book with a cover like these to read the blurb and probably buy it. I never saw these back in the day but I daresay I would have bought any of them and searched high and low for the rest, obsessively.
Here are all the covers: https://www.thriftbooks.com/series/saga-of-the-phenwick-women/49884/