Not sure if there's an official name for either alliance, so I'm going to call the Prussia-Russia-Italy-Netherlands-Greece-Spain alliance PRINGS, and the French-Austria-British-Ottoman alliance FABO.
As strong as the PRINGS alliance are, all France and GB have to do is hold off Spain, and neutralize the Dutch as a threat before lending aid and a naval blockade against the Prussians. After having gone through the slog of having to mow down wave after wave of Austria's infantry, the Prussians will likely collapse against the combined might of three major powers bearing down on them. The Italians don't have the manpower or hardcore strength to wage a long-term offensive, so unless they can score a quick offensive victory, they're looking at shoring up Venezia and Milan for most of the war.
Really, the FABO have this war in the bag if they can hold out long enough to have their forces offer a united front against their enemies. Total victory need not be a goal, just a delay long enough that the enemy bleeds too much to wage an offensive war. For the PRINGS to win; a quick, decisive offensive early on in multiple fronts will be necessary, as well as keeping the FABO disunited. The advantage is heavily on their side early on, but I think a single major defeat in an offensive will be enough to turn the tide to something less one-sided.
But, this of course assumes that Austria and the Ottomans are devoting their full attention to staving off their main enemies. Investing in a huge navy was probably a bad call for Johnny Turk: the combined French and British navies make the force redundant, and that money could have been better spent shoring up defences and recruiting soldiers. Austria will have to pick up the slack, and be willing to conscript a metric shit-tonne of cannon fodder.
