Marvel does a bad job sometimes when it comes to this sort of stuff.

For example the Bucky from the Heroes Reborn universe is supposed to be the counterpart of a dead child from the 616 timeline. But in that Heroes Reborn reality that female Bucky is the granddaughter of the original Bucky and Peggy Carter. In the 616 timeline Bucky and Peggy don't have a child or grandchildren together.


To me if your alternate reality doppelganger doesn't share your same first and last name, your same exact DNA or has different people as parents...then it's not a doppelganger.