Hi...
To get good results from Headshot you need better photos. All the photos you show are unsuitable for one reason or another.
When working in Auto mode you shouldn't use photos of models with extremely long hair as the bottom will be cut off. Short to medium length is best. You also don't want to use photos where the hands are up near the face. You need to ensure nothing is obscuring the face or hair.
In Pro mode you should use photos where the hair is off the face. Photos where the hair is pulled back are best otherwise you will need to do a lot of post work to clean it up. You also don't want to start cutting around the face like you have done in your second screenshot. Just use a suitable photo to start with and you won't run into the problems you show.
Please see the guide below which shows which images are suitable and which are not.
https://manual.reallusion.com/Headshot_Plugin/ENU/Headshot_Plugin_for_CC/1.0/ID_PG.html
Peter
Forum Administrator
www.reallusion.com