Polish Cossacks are essentially Ukrainian cossacks who fought for Poland
Dude please stop, lesson in Polish History for you.
Cossacks were not an ethnic term, ever.
Eastern Ukraine, Crimea and adjoining lands that are now Belarussia and Western Russia were a Polish frontier exactly the same as american Wild West.
Cities were few and far between, there were vast forests and steppes, whenever a peasant tried to escape servitude or criminal avoided justice he went there to live "po kozacku" Cossacks were a social class in Poland, mercenary soldiers who normally lived in fortified camps or communes hunted, farmed and fished and in times of war were employed by Poland as light infantry/light cavalry.
As such Cossacks were Ruthenian (no such things as Ukraine or Ukrainian in that period) Polish, Russian, Tartar even.Polish Cossacks
were native Poles who joined the Cossack community and there was a LOT of them (at least as many as Ruthenian Cossacks).
Galicia was always predominantly Ukrainian
No it was not, please refrain from posting bullsh*t about our history that you obviously dont know.
Can any one tell me of them because there doesn't seem to be much info about them.
Thats because of a certain phenomenon that took part in Ukraine, social elites adopted Polish culture (nobles, princes, merchants, soldiers etc) while peasants typically entered the ruthenian culture circle, it is estimated that at least 20% of all Cossacks were native ethnic Poles but after a generation their kids (being Cossack was hereditary after a fashion) lost their Polish roots.
Also there was no difference in the lifestyle of different Cossack ethnicitie, they all joined the Sich fortified camps and followed the same code.
These people were part peasants, part farmers, part pirates (they raided Turkish coastal trade regularly), part mercenaries, part bandits, by XVI century they became trained professional mercenaries for Poland.