Never would have occurred to me to guess Russia but they were the first ones? Well if they were first and Finland was declaring independence from them... why did it take everyone else so long to recognize them? Strange.
Depends whether the Bolsheviks constituted the legitimate Russian gov't at the time. This was very shortly after the October Uprising had toppled Russia's provisional gov't. The Bolsheviks had promulgated a doctrine of national self-determination & accepted the break-up of the Russian Empire. At this point, Bolsheviks still believed in the coming global revolution that'd abolish conventional national borders soon enough anyway. They had a precarious hold on power in Russia itself & little chance of forcing breakaway nations to remain within the Russian polity. WW1 added to the diplomatic difficulties & probably delayed recognition as third countries were speculating with various possible outcomes in Russia. The Finnish Civil War in early 1918 further complicated things. Then, the Finnish gov't briefly alienated some of the Allied powers by attempting to import a German-born monarch to her throne. Very complicated, all in all.