A member here pointed this out to JDW on twitter , that by today’s logic with the cloned bodies and mind/memory back up Jean and Phoenix were the same but he just stated that by conclusion of Inferno that they were the same character (the portion of Jean that was in the Phoenix copy/merger was returned to her).
To me if your body is copied and your memories /mind transferred them it is you because our soul is what is in our brains.
Edit: I’m on my phone and don’t type well on phones.