These were several books by the same author, but not a series. My 7th grade school librarian introduced me to the author. This would have been around 1985-86. The books all dealt with old, haunted houses in New England. One had a creepy basement with a dirt floor, and bodies buried under it. Another had a person look out a third story window to see a face looking back, and knew it was a ghost. These books felt very grown up to me at the time, but were definitely Young Adult. They were eerie and moody, but not Stephen King scary. It was a woman author, and the covers usually had an old house in silhouette. I’d love to revisit this author, as I read all of the books in our school library over and over. Some faint memory says the authors name might have been Barbara something……
Stab in the dark, but maybe Barbara Michaels? She wrote lots of books in the 80s with a gothic vibe. Though if you look up her books, I’m pretty sure the covers were updated at some point.
It seems like Barbara Michaels to me, too. ‘Ammie, Come Home’ was televised as ‘The House That Would Not Die’. Does youtube have it? (BTW, she also writes as Elizabeth Peters, Egyptian antiquities female sleuth, if that prompts any memory.)
Janet Patton Smith? She wrote The Ghost in the Swing and others like it.
Could be the Tradd Street series by Karen White. Also, it’s possible the one with the third story ghost is Karen White’s “The Beach Trees”.
Could the author be Ruth Chew?
I don’t know if any of these would be helpful, but Betty Ren Wright, Mary Downing Hahn, and Joan Lowery Nixon wrote a number of scary books about ghosts around the time you’re thinking of. I’m not sure if any of these are it, though, because I don’t remember the kinds of covers you described. But, maybe looking at these might suggest other possibilities. Hope it helps!