A third cousin I was corresponding with has made a very interesting suggestion as to why my great-grandfather (her great-great-grandfather) and his brothers changed their last names >from Krasinsky in 1890 when they left Nova Ushitza for Manchester. She said she knew of one of her other relatives who did the same thing because he was seeking employment or perhaps had been sponsored for employment >from a German-Jewish factory employer in Manchester, and the relative understood that a "German-Jewish" sounding last name would work better than a Russian sounding one in terms of obtaining employment by German Jewish factory owners.
I had wondered how and why three brothers could emigrate legally >from the Russian Empire under totally assumed names if they needed visas and passports. I didn't find this particular novelty among any of my other ancestors, so the suggestion about employment seems to make eminent sense.