It appears my Great Grandfather, Gabriel Loranz entered the US in 1919 under an assumed name. I cannot find any previous record of him anywhere in the world except for a birth/death record of a 1 day-old baby boy (Lorenz) born on the same date, 16 February 1880 in Stuttgart.

Has anyone else confronted this type of brick wall? How do you research further?

I've spoken with all of the living relatives who knew him, and they can't tell me anything more than what he told them. "Born in Odessa, 16 February 1880, Brother named John.

ALL documentation of him is from his crossing the Canadian/US border in 1919 (under the name Gabriel Lawrence), and later. There is absolutely nothing before.