Are the casualties of the superbombing of Petrograd counted separately? OTL St. Petersburg had a population of ~2,415,000 in 1916, and
around 2,812,134 people by the beginning of the Great Patriotic War. IOTL the Russian Civil War and the ensuing famines led to St. Petersburg's population slipping behind Moscow for the first time, but
presumably Piter remaining the capital city would bolster its population compared to OTL and thus see at least 40-50% of its citizens succumb to atomic hellfire and its consequences?
Seconded. I would have issues with using only real-life people beyond a certain point and hew too closely to their OTL activities in dramatically different circumstances, not to mention that a lot of post-Soviet politicians have strong ties, particularly familial ones, to another country - like
Mykola Azarov the 14th Prime Minister of Ukraine (born in Kaluga to an Estonian father and a Russian mother), and Alexei Navalny as stated above - that just would not be there in a world where Ukraine, Belarus and such retain their independence for a century longer.
Though I do have to assume Mikhail II and the regime that existed until the end of the SGW actively organized and sanctioned purges and pogroms against enemies of the state, particularly Jews.
Also I agree with
@BigAbeRangel that your post regarding Actionist Mexico is
excellent, and would perhaps be even more plausible for a rendition of TL-191 where the Confederate States is less... lucky and/or ascendant, shall we say.