I have the same story in my mother’s maternal family, who came from Vilna. My great-great-grandfather, Reb Yussel Weinstein, was originally a Romm. To avoid conscription, he was “adopted” by a childless Weinstein relative. I believe money also changed hands. This was supposedly legal. He was born in about 1803-8. I cannot find any records of these Weinsteins and don’t know his wife’s maiden name. Reb Yussel was a rosh yeshiva, and somehow his wife, Bubbe Zelda, became a commission merchant for Polish nobles, with agents who bought property, jewels, and Arabian horses for the nobles. And she had 8 children and lived to be 104-106 years of age. How did she rise to such wealth and prominence? All I have is a narrative my mother wrote, full of anecdotes fro her mother, Zelda’s granddaughter. They had a daughter who married a brother of the sculptor Mark Antokolsky. I contacted a descendant of his family, who didn’t know any family history. My grandmother’s sister, Celia, became a governess, who married a wealthy cotton plantation owner, Itcha (sp?) Pollack, from Tashkent. Their plantation was taken by the Bolsheviks, but They let Itcha run it. Later, their son, an engineer, was given an apartment in Moscow for his family, including his parents. I know this is true because family friend visited Aunt Celia after the Revolution and W W I.
Anyway, what is my next step? Should I hire a genealogist 
to pursue my quest? I even traveled to Vilnius but was unable to learn anything there. I was on a trip with friends.
Thank you for any help anyone can provide!