Well, that's pretty much were the real early-1918 German, Bulgarian, and Austrian plans for Balkans and Europe.
And Ukrainian/Polish borders do make sense, Germans used Congress of Poland borders, when establishing a kingdom in 1916, and in case of Ukraine, those were governorates claimed by UPR in 1917 and early 1918. Hetmanate also claimed Chelm, Polissya marshes( Pinsk-Mozyr area south of Pripyat river), and Belgorod.
Regarding Courland, Livonia and Estonia - those are internal borders. All three regions are supposed to be in United Baltic Duchy, a state run by the Baltic Germans, and theoretically, subjected to annexation into the Reich down the line. I doubt that it would have happened, however.
Lithuania - they held the claim to Belostok-Grodno-Volkovysk area since the Duchy times, and they didn't really care that those lands are full of Ruthenians(Belarusians) and Poles.
Sometime ago on KR mod subreddit someone ran math, and we discovered that Lithuanians would make 40-45% of population in those borders, followed by Poles, Ruthenians and Jews.
The most problematic of all the new configurations are actually Bulgaria and Lithuania. Their titular nations are like just a plurality.
While Bulgaria has a cop out with integrating Macedonians, who didn't have well defined identity at the times and oscillating between identifying Serbian and Bulgarian, as Bulgarians and therefore reaching majority, Lithuania would be very fragile.
Serbia is effectively dead , and it'll take them probably until 21st century to recover.
Another question is as of 1919 still non-existent Belarus. Per B-L Treaty, this is just Russian land occupied by Germany. Belarusian cultural and political leaders of the time lobbied hard for independence, but Germany lost in our world. As of 1920, Belarus basically had no national identity and its population was very diverse...