No, the murder of the royal family in 1918 was not relevant in any way to the outbreak of World War II. By this point Nicholas had already abdicated and been placed under arrest, as well as his entire family. The Bolsheviks controlled the organs of government in Moscow and St Petersburg, and even among the many disparate White Army forces, the idea of a restoration of Tsar Nicholas was not popular. Anti-Bolshevik they might have been, but the majority of them were not pro-monarchy, or at the very least not pro-absolutism. As soon as Nicholas abdicated and the monarchy was abolished, the Romanovs ceased to be a relevant political force in any practical way. At most they were useful figureheads to inspire the more conservative and traditionalist Russian peasants that were anti-Bolshevik.

The Bolshevik victory in the Russian Civil War is a considerably more relevant event that laid some of the groundwork for part of WWII, namely the German invasion of the Soviet Union. But it should be noted that German-Soviet relations were relatively positive in the years of the Weimar Republic - there were multiple socialist and communist parties legally operating within the German Reichstag, and for several years the Soviets allowed German soldiers to train at military installations within the USSR (as a way to get around the strict terms of the Treaty of Versailles). Only with the rise of Adolf Hitler to power in Germany did these positive relations begin to sour.