I'm confused about the ending ...

WARNING: This post contains spoilers. If you haven't seen the movie and still want to watch it, please do not continue reading!

I recently watched Hammer’s Blood from the Mummy’s Tomb (1971) and learned about the 1980 remake The Awakening with Charlton Heston. After watching it, I read a review by Roger Ebert. Ebert disliked the film, and I mostly agree with his assessment due to its slow pace, logical gaps, lack of suspense, and absence of scary scenes. However, I found the ending to be unusual and a departure from the typical happy ending expected in such films.

However, the ending raises new questions. Maybe you can help me?

1) What is the meaning of the scene where baby Margaret appears to die and then revives? Is the original Margaret dead, with the spirit of Kara now inhabiting her body?

2) Is Kara inhabiting a new body without realizing it? Margaret appears unsettled when she sees herself in the mirror and seems to have phases where she no longer seems to be herself. What’s going on?

3) I’m confused about the ending. Heston tries to save Margaret by transferring Kara’s spirit into the mummy, but Margaret ends up becoming Kara. However, it’s obviously suggested that Kara’s spirit has been in Margaret’s body since her birth. What’s happening in this scene?

4) It appears that Margaret is no longer herself from the scene where she kills her psychiatrist. In the subsequent hospital scene and at the ritual at the end, she already seems to be Kara. So, what is happening in the ritual scene? It appears that Margaret is already no longer herself before the ritual, before she has that blue Egyptian make-up.