A very interesting articleCampaign against Prussian Poland
Germanisation policies in the Province of Posen mostly failed. Although most of the administrative measures aimed against the Poles remained in force until 1918, between 1912 and 1914 only four Polish-owned estates were expropriated, while at the same time Polish social organizations successfully competed with German trade organizations and even started to buy land from the Germans.The long-lasting effect of the Polish-German conflict in the area was development of a sense of Greater Polish identity, distinct from the identity common in other parts of Poland and primarily associated with nationalist ideas rather than socialism, prevailing in other parts of the country in 20th century.
"It seems indeed that the nobility who encouraged the Jews to settle were protestant when they did so. (Jews had been there for centuries)"
False. It was King Kazimierz long before protestants.
By the way it is strange to talk about protestants and catholics with people from country durring religous war. Look on Northern Irleand.