Shadow Problem with Doppelganger

Doppelganger Experiment 1 from Munirat Plummer on Vimeo.

From these test shots and in the screenshot you see below, I have thought about a problem which might affect the visual outcome of my video. I think that the shadow cast by the doppelgänger needs to be subtle so that it is easy to see that it is a paranormal aura.

I might have to consider using green screen to film the doppelgänger's scenes because this will allow more freedom when I want to edit and add any effects on it.

My next test shot will be more precise because I am now going to consider lighting in the scene so that the horror/thriller theme will be obvious. I am going to do this test because it will allow me to see the shadow of the subject since its going to be more obvious and harsh due to the contrast lighting I am going to have.
In the test shot I shall be testing the scenes from my storyboard and I can see if it will work or any changes that need to be made.

The previous test shots I made has allowed me to notice this new problem which could have easily been overlooked.