I agree with Podkarpatska. Alas, I have nothing much to add, except to say that the relevant dates here are neither 1787-1792 (those years are a joke, for Galicia, the heart of Greek Catholicism, was already out of Poland for 15 years by then!) nor 1677, but 1375. The year 1375, when the Polish conquerors, with the Pope's blessing, installed a Latin bishop in Przemysl, demonstrates clearly the Latin intention in connection with the Ruthenian Voivodeship. One may also consider what happened in the 1400s and 1500s to realize that the number of parishes that entered the Union of Brest in 1596 was considerably smaller than the number of Ruthenian parishes which had existed ca. 1400. This is because a good number of those Ruthenian parishes had already been Latinized and/or Polonized, and this continued into the 17th, 18th, and 19th centuries. See the work of Fr. Ioann Polianskyj. I know of several places in Poland today where the inhabitants are actually Polonized Ukrainians, and have been for centuries. The Union of Brest was motivated by a desire for the Orthodox bishops to secure political advantages, of course, but also by a desire to preserve the rite against these encroaching Latinizations, which had been relentless. That the brotherhoods in the cities didn't go along with the program was of course problematic for all concerned. But in the villages, most peasants were oblivious. The stories of them securing Russian priests are true. But villages often flip-flopped back and forth - they secured priests from any handy source. They didn't much care whether they came from Russia or Poland, because the villagers couldn't much tell the difference anyway.
The last Orthodox monastery in Galicia, the Maniava skete, was closed in 1785. There was one Orthodox parish that continued to function in L'viv throughout the Austrian period, but it served as a diplomatic outpost more than anything. Most villagers did not even know that they had become Greek Catholic for centuries, nor did many know what that meant. Certainly most in the villages, which was the bulk of society, did not know until after the revision of the service books following the Synod of Zamosc in 1720. For all intents and purposes, following the political determinations of their bishops, the Orthodox Ruthenians had largely gone into exile under the aegis of the Greek Catholic Church. All of the Ruthenian Voivodeship would have participated in this fate had not Russia encroached on Polish territory throughout the 17th and 18th centuries. As late as 1768 there were still many Greek Catholics on the banks of the Dnipro River in Central Ukraine. It was in that year, of course, that the Kolyvshchyna happened, when the Orthodox rose up against their Polish overlords and tragically murdered many of their Greek Catholic brethren. This is a sad chapter in Ukrainian history.
As of the late 19th century, the Russophile parties in Austria began to agitate for a return to Orthodoxy and/or a reunion with Russia. They were tolerated at first by Austria but then repressed when alliances changed and Russia became an adversary of Austria. It was these priests, having gone over to the Russian Empire at Kholm, who formed the backbone of the effort which abolished Greek Catholicism in the Kholm Eparchy in 1875 and forcibly reunited it with Orthodoxy. There were also members of the Russophile party which wished to join with Russia and remain Greek Catholic. The Ukrainophile parties were split between those who wanted to remain Greek Catholic and others who were simply anti-clerical and wished to usher in a secular socialism. The Ukrainophiles were actually opposed to Metropolitan Andrij Sheptytskyj at first, as they considered him a Polish sympathizer. His middle way actually brought the Ukrainophiles and the Greek Catholic Church together. The Greek Catholic Church was a dying element before Sheptytskyj got there. It was a second-class entity and was steadily becoming more and more Latinized and Polonized. Sheptytskyj was a believer in the Roman Catholic doctrines, but he, above all, managed to preserve the eastern ethos of the rite.
Of course, the rise of the II Polish Republic in 1918 gave the opportunity for the Orthodox -- mostly these starorusyny -- to reassert themselves in Galicia again. But the Ukrainophiles also began to be drawn to Orthodoxy, in the form of an autocephalous Ukrainian Orthodox Church.