Short answers, pulled from the story.
The Kingdom of Yugoslavia was officially renamed on the 3rd of October 1929. This change occurred after the Conference of Ambassadors in Paris granted international recognition to the new state on the 13th of July 1922.
King Alexander I was assassinated in Marseille by Vlado Chernozemski, an experienced marksman from the Internal Macedonian Revolutionary Organization. The assassination took place in 1934 with the cooperation of the Ustaše, a Croatian fascist revolutionary organization.
The official Yugoslav post-war estimate of victims in Yugoslavia during World War II is 1,704,000. Subsequent data gathering in the 1980s by historians Vladimir Žerjavić and Bogoljub Kočović showed that the actual number of dead was about 1 million.
Slovenia and Croatia became the first republics to declare independence from Yugoslavia on the 25th of June 1991. The following day, the 26th of June, the Federal Executive Council ordered the army to take control of the internationally recognized borders, leading to the Ten-Day War.
The war in Bosnia and Herzegovina lasted more than three years and resulted in the almost total emigration of the Serbs from all three regions. The conflict also caused the massive displacement of the populations in Bosnia and Herzegovina and the establishment of three new independent states.
Montenegro became an independent nation in June 2006 after the results of a May 2006 referendum. This event rendered Serbia and Montenegro no longer existent, and Serbia became the legal successor of Serbia and Montenegro.