Weren't they her Grandparents? IIRC (and I may not, this was so long ago) she inherited the house. At the end when she's become one of them, she's heard talking to the other entities, hoping that someone else would come and open the fireplace which had been sealed again (with them inside). That's my memory of it.
As for Trilogy of Terror, that's another great childhood memory
Ah, those were the days!