Nothing is inevitable. But things got very dicey after the Triple Entente expanded its obligations into the Balkans after 1911. This essentially handed the match to the magazine to revisionist Serbia.
Agreed. None of the great powers wanted a "European war"; even Germany was confident that the war would be l
ocalised for quite a while. But Russia, convinced that Austria-Hungary was being aggressive in the Balkans, gave Serbia what amounted to a guarantee of support against Austria-Hungary in any circumstances, and even though Pašić (the Serbian head of government) was a cautious man he was politically unable to restrain the pan-Serb nationalists who did because of public support for those nationalists. By giving Serbia this guarantee, the Russian government (perhaps inadvertently) made Serbia far bolder than they would have dared to be otherwise, and thus placed the trigger for a European war in the hands of a country whose head of government couldn't control what its government was doing; the fact that the Russian ambassador to Serbia openly backed the pan-Serb nationalists as a matter of ideological principle didn't help in this regard either.
I'm not sure of this point, but simply having there be a different Russian ambassador in Serbia might well have prevented WW1 occurring as we know it.
The continental nations' pigheadedness are the ignition points, Ferdinand's death just got the ball rolling. Had they believed that Britain would be willing step in then I don't think the war would have happened at all. In my opinion the real cause of WWI was that everyone expected someone else to back down when it came to supporting their allies. What was expected to be similar in scale to the Franco-Prussian war turned into a nightmare.
Agreed. Bethmann Hollweg, the German Chancellor, genuinely believed that the United Kingdom was going to remain neutral until such a time when it was too late for Germany to back down because the crisis had heated up to the point that any concessions at all would be seen as a shameful surrender.
Austria was still unstable and likely to break apart eventually giving Germany the opportunity to snatch up pieces and satisfy their expansionism.
The tendency of Austro-Hungarian instability is exaggerated, mostly due to post-war Entente justifications for why they broke up the Habsburg empire. Austria-Hungary was enjoying lots of economic growth, and it was actually developing much more successfully than the various nationalist, unstable nation-states that were hailed by the likes of Woodrow Wilson. It was less stable than, say, Britain or Germany but arguably more stable than the Russian Empire; hatred of the Austro-Hungarian authorities mostly came from nationalists from outside the Habsburg empire, not within. As for Germany, turning on the only great power that was friendly to them, in a situation where France and Russia are deeply hostile and Britain is leaning towards hostility, would be too stupid for any sane politician. (The category of 'sane politicians' does not, of course, include the extreme pan-Germanists, but they weren't in power and weren't likely to get there under the
Kaiserreich.)
Then, to revisit the flipped question, does that mean (1) that if the outbreak of a Great War can be delayed for three years, then a conflict meeting OP parameters would become unlikely and only less likely as time went on; and (2) that avoiding the Franz Ferdinand assassination would be enough of a PoD to do this?
This depends on your PoD. If it's just that the assassination attempt on Franz Ferdinand fails, no; the pan-Serb nationalists will try again and sometime they'll get caught, even if it's when they've (e.g.) distributed literature inciting rebellion rather than something as grand-scale as killing the crown prince. If it's the PoD I mentioned above, where Russia doesn't encourage Serbia as much, then yes.
If the Serbian pan-Serb nationalists aren't encouraged with Russian support for their expansionist ambitions, Russia and the United Kingdom will likely dissolve the Anglo-Russian Convention when it comes to be renewed in 1915. True, Russian power is increasing, but give it enough time (especially as the German naval threat becomes less worrying, as the British Empire's naval lead over Germany was constantly increasing at this time) and the British will be quietly searching for how to take the Russians down a peg.
But Austro-Russian disagreements over the Balkans are inevitable unless you have a PoD several decades earlier; I can talk about the reasons why at more length but that would derail this thread. So it's very difficult to imagine any great power conflict in which Austria-Hungary and Russia aren't on opposite sides.