Did the Russian Empire/Soviet Union ever attempt to make outer Manchuria and modern day Kazakhstan ethnically Slav/Russian? Was it ever done on the same level as the Russification campaigns in Ukraine?
Sorry for late answer. But yeah kind of, they replaced the writing system in Kazakh to cyrillic. And halted their nomadic-lifestyles, many Russians colonized the northern parts of the country too. Making it favorable for every Kazakh to learn Russian. As Kazakhs is a turkic-speaking people slavifying them would be difficult.
In the Soviet-era Russians was the majority of the Kazakh-SSR.
Meanwhile Outer Manchuria can now be counted as entirely Russian. There used to be many Koreans there but they was moved to Central-Asia by Stalin.