Yamalo-Nenets, Udmurtia , Mari - show the most their original folklor, other is have a strong Slavic folklor influence imo. But for Karelia is another example - https://www.youtube.com/watch?v=n989zmuvnnc , It seems to me that imitation of Finland folklor
Yes, at least part of them. But kremlin's liar ideology call all of these Finns, Ugres, Ogres, Chukchies, Gypsies, Moksha, etc nations with a fake selfname "russians". The same non-national term, which consists in slavery of these nations in "russian empire" => USSR => "russian federation". All nations who do not become a rootless goatfaced scum in satanic experiment of human devolution back to monkeys - "russians" - must be free!
And remember that "russians" - are fake nation, who are watchdogs for dozens of real nations in terrorussian jail of nations! This language are not any kind russian, and not any kind Slavic. Every national attribute of "russians" are stolen from different nations, or falsified, cause robbing the most reach territory in a world - is a big business.