Though we can knock off a few on the list, Beria for one. He doesn't have the powerbase nor the support of Lenin. Stalin also set the precedent for non-Russian leaders so if a Russian gets in, I think its forseeable that future leaders (if there are any) will be Russian as well, with little variety.
It'll be Rykov, though Zinoviev and Kamenev will be powerful voices. Tomsky will also do better. Bukharin is likely to remain the intellectual poet/daydreamer he was IOTL. Beria will likely never make it to Moscow without Stalin.