Why did uncle Bill set Nora up to be a victim?

SPOILERS DISCUSSION

So it appears that creepy uncle Bill set up his own niece, Nora, to be the dead druid sorceress' template for returning to life in a fantastic new, mummy twist. It begs the question of whether Uncle Bill harbored incestous leanings for Nora, or was Nora a convenient, beautiful and available victim. In the movie, Bill doesn't say or do anything to this niece, Nora, that would suggest he has inappropriate urges for her, which makes me wonder if uncle Bill was manufacturing his own druid partner and Nora was a convenient victim, beautiful and all but it would still be creepy to be with someone who looked identical to a blood relation such as a niece.

It dawned on me while watching THE ETERNAL for the umpteenth time, that here was a slightly new twist. The monster is still a supernatural horror, but that of a beautiful woman, a malevolent doppelganger of the beautiful Irish-American Nora. But in THE ETERNAL the director gives us the supernatural fiend we come to expect from occult, spooky, supernatural gothic thrillers, but in the form of a beautiful woman. What more fiendish a monster.

The doppelganger tries to be a replicant of Nora. If you watch the movie closely, the doppelganger's replicant strategy is flawed. In endeavoring to replace Nora with its physical replicant self, the doppelganger picks up Nora's personality traits, like the maternal instinct for her son, Jimmy, and flaws such as Nora's alcoholism which the husband uses against the doppelganger to buy time. If you want to switch places with someone it's probably best not to imitate them too closely.