It is true that there was indeed support for local left-wing parties in the Baltic States before the Russian Revolution. In the case of Estonia and Latvia, there were among the primary forces fighting for their independence or at least autonomy. Lithuania was a bit more complicated than that, but the Social Democratic Party of Lithuania (at the time a much more left-wing party than social democratic parties today) was an important part of the National Revival. It wasn't hard for left-leaning nationalists to agitate here - after all, it's only natural that if the source if oppression is an intolerant autocratic monarchy, then the best solution would be to steer as far away from that as possible and establish a socialistic system, right?
However, despite that, I do not believe that it is possible for the Baltic States to go communist on their own while still keeping the OTL Russian Revolution. Simply enough, the socialism Baltic national movements exhibited was far from the Bolshevism which took over in Russia, which means that the Bolsheviks would find little popular support here if they tried to take over. And it works from the other side, too - the Bolshevik takeover of Russia and the Wars of Independence against them usually discredited the Baltic left-wing (much like what happened in Lithuania, for example).
The only possibility for this scenario is for the Bolsheviks to just brute force their way through and occupy the three Baltic states during the RCW, but while that is an interesting scenario, I don't feel prepared enough to detail it right now.