Yes, “Cossacks” have been in the news since the late days of Gorbachev, but I’m not sure if they could be taken seriously and if yes, whether they are related to historical Cossacks. It seems to me that the societal shifts of the 1990s marginalized enough people to build up supply of manpower for a new Cossack estate. I’m only wondering if this is what Putin has in mind.
I’m sure that Cossacks were as multi-ethnic as one can imagine but most must have been either Slavic or Turkic by virtue of the Eurasian steppe’s location.