Nah, lets assume first diplomatic and other changes appear no earlier then, say, oh, 1910. Too bad, because just like Germany Austria could profit from some more concentrtaion on land forces instead of the navy, but, eh.
Ignoring details, would France have much trouble with a sudden second invasion? Could it quickly enouh reroute troops? And if it does, would that crucially weaken the front against the Germans?
Also, with the forces Austria now does not have to muster against Romania and Serbia, could it have more susccess against Serbia and Russia? And lastly, would Russia react to a Swedish invasion of Finnland, or concentrate on Germany? Could Russia even react? Their slogistcis and supply situation apparently, ah, wasnt the best, after all...
Well, the Meuse-Argonne offensive I mentioned in t'other thread can be cancelled, and men sent south. However, since the PoD is pre-war, there's a lot of potential for weirdness. In short, France did IOTL have an army deployed down on the Italian border because Italy was a member of the Triple, and Joffre shifted them north (and reorganised the army in general) to allow for offensive actions against the Germans. If Italy's clearly pro-CP, then he won't be able to do this and there will almost certainly be an army down there waiting for Italy's entry. This also means that the initial French offensives either won't have occurred or, if they did, will have killed fewer French and Germans on account of being smaller in scale.
Wrt to Serbia, she's fucked, to put it in common parlance. Her only hope is surviving through some combination of wackiness and zaniness. The Russians do have a covering army for Finland in '14, 4 Schuetzen Brigades and 5 divisions, but just looking at 50th Infantry Division's movements, I suspect these have all been thrown into the front line by OTL '15. With a more aggressive Sweden, this may not be the case, but they might not get priority for arms and equipment. However, that might be offset by the short supply lines and the fact that they're in essence defending St Petersburg.
The Russians did manage to launch the Brusilov Offensive in '16, even if it did end up over-extended, so don't count them out completely. That said, I wouldn't like to be in the position of the Admiral von Essen, their Baltic Fleet Commander, with the Swedes and Germans against his forces, he's even more badly outgunned than IOTL.
A 1910 PoD . . . Italy had already laid down Dante Alighieri which caused the Austrians to reply with the 4 Tegetthoffs. However, funds were refused by the government, much to everyone's surprise, leading the Austrian naval chief to lie to everyone and pretend that private industry was going to pay for them. He took a 32 million crows credit on his own head to get them started. So if you kill him (ah, P's murderous instincts again

), or have the truth exposed scandalously, then you've killed the ships, too. And probably Italy's
Andrea Doria and her sister,
Duilio, not to mention the
Caracciolos.
IOTL a Naval Convention of '13 was signed between A-H, Italy and Germany providing that in the event of war in the Med an A-H admiral would have command of any combined fleet. But I'd imagine that would be an Italian admiral if the Ts aren't built ITTL.