What do you think happend to Tracy after the last scene?
SPOILER AHEAD
My guess is Tracy was killed by a Charles Possessed Quentin who then resumed living at Collinwood with a resurrected Angelique as his new bride, and for a plot twist have Tracy come back as a ghost who is doomed to occupy the house and be eternally tormented by the sight of her husband living a new life with another woman.
Another theory is instead of getting killed by Quentin/Charles her life got spared after being blackmailed by Angelique to assume the role of Collinwood's new housekeeper with Carlotta and Gerard kept around as ghosts to keep her inline in case she tried to escape the estate.
What do you think?