In another similar discussion I had mentioned the reasons why personally I disagree with Dolores Cannon's view and how I find many inconsistencies and contradictions in such approach.
However, independently of the so many factors why someone carries the energies of another individual soul, there is a very accurate way to know who is the real person whose soul fragments/energies belong to: by getting to know the real soul vibration or energy signature of that individual.
There are already a lot of people who identify with the energies of Joseph and Jesus, not just those two cases, also there are lots of Mary's, lots of Lucifers, lots of Cleopatras, lots of AA Michaels...and so on.
This can be done with practice. First it is very important to get to know one's own personal soul vibration or signature. It does not matter then how different your aspects or past incarnations are in the spectrum of personal traits and frequencies because once you really get to know your own base vibration/signature, then it is much easier to really know which are your own incarnations.
Once you get to know your own soul vibration, then it becomes easier to recognize the soul vibration of another individual and that way you can track their incarnations.