All of this "who did what to who and when" is merely clouding what is a very simple issue.
The Serbian government sponsored a terrorist group and harbored a militant anti-Austrian streak in their efforts to rebuild a "Greater Serbia". Austria was fully justified in retaliation.
Responsibility for whether or not the war was localized is entirely on Russia for becoming involved, at the urging of the revenge-mad French.
Did the Central Powers provoke war? That is totally absurd, you don't provoke a war in which you will be outnumbered and surrounded at the very outset. Even Hitler wasn't that crazy.
Nonsense. First of all, Austria didn't even *know* of the existence of the Black Hand until far into World War 1.
Second, there appears to be no evidence (and you will fail if you even try to find such) linking the Black Hand with Serbia's in-office government. Moreover, there was a power-struggle going on inside Serbia's government that would have precluded such state sponsorship.
The assasins themselves were mostly high school students with a history of anarchism of random violence for the sake of "making statements."
Serbia rounded up at least 7 of the 9 assassins, possibly more, and turned them all over to Austria. That hardly amounts to protecting them from Austria. I'm aware of only one of those assasins even surviving eventual Austrian justice.
That's poor logic. Of course Austria provoked a war. Austria didn't even negotiate after it decided that Serbia's capitulation wasn't good enough. Austria invaded Serbia, knowing full well that Russia would enter the war.
This was a cold and calculated political decision to provoke a war. It took Austria two months to write up their demands, and their demands against Serbia were so severe as to make it clear that Austria wanted war at all costs. Moreover, Austria was provocative by giving the Serbs a mere 48 hours in which to respond.
Furthermore, the writings of the day indicate that Austria's biggest concern was how to drum up their own public support for such a war prior to invading.
The great mistake was Germany's "Blank Check" promise to support Austria in a war; Germany had underestimated the Austrian desire for war at all costs.