In order to contain Russia, I think the Entente would have two options: 1.) Austria and Russia come to an agreement regarding the Balkans. Romania and Bulgaria are in the Russian sphere, and Serbia and Greece are in the Austrian sphere, as is Albania - France, Britain, and Austria make some ambiguous promises regarding Constantinople to Russia. 2.)If the Entente cannot guarantee Russian neutrality or add them as an all, then Britain's alliance with Japan comes in quite handy, since they can promise a free hand in Manchuria/Vladivlostok and northern Sakhalin. Or again, maybe a combination of the two possibilities.
Archduke Maximillian and/or Kaiser Rudolf decide to ride roughshod over the Hungarian nobles and grant universal male sufferage - the 'kingdom of Hungary' still exists, but the myth of Hungarian majority is destroyed. An uprising occurs centered in Budapest against the new laws, which lasts a whole year before it is put down by the Imperial Army. Dalmatia is added to Croatia, which they (the Croats) wanted. Rudolf and Maximilian make promises to the Czechs to establish a 'kingdom' of their own, but at the same time they promise the German minority that they will have equal say in the government.