Kaplan or Caplan is also a surname common among Ashkenazi Jews, usually indicating descent from the priestly lineage (the kohanim), similar to the etymological origin of the common Hebrew surname Cohen. One of the earliest modern records of Kaplan as a family name is that of Abraham Kaplan in 1698.
Nope, Ashkenazi Jews are Jews.
The Khazarian Myth is a a psyop.