Here is what I have on the Venai family, all written around 1916 by Charles Johnson. Maybe you can tell whether this is the same Venai family. If so, I can send more.

“Maternal Grandparents of Charles Johnson:
John Venai – native of Stuttgardt or Strasburg now of Germany – was married at the Trinity Lutheran Church, Lancaster, Pa., under the name of Johann Wienay to Catharina Stahl, August 7, 1817. Dates of his birth lost. He died July 4, 1839, at S.W. corner 16th and Sansom Sts, Philadelphia. Catharine Stahl – his wife – was born in Harrisburg, Pa., July 16, 1792, died at S.W. Corner 16th and Sansom Sts – her own home – owned by herself – Philadelphia – May 28, 1867.

John Venai spelled his name various ways. When his first child Marie was born it was spelled on the Trinity Church record, Vienai; when my mother Sarah Ann was born it was spelled Wienai; when Caroline and Amanda, twins were born it was spelled Winnai; when Catharine Louisa was born it was spelled Vinai. John Venai was a well educated man – he spoke six different languages. He served under Napolean 1. Was a lieutenant. Was taken prisoner at Moscow, and fought at the Battle of Waterloo. He emigrated to America with Joseph Bonaparte about 1816. Settled at Lancaster, Pa., Carried on business as a tailor employing 25 persons. Lived on North Queen St, on the N.E. corner opposite the present market house, about two or three blocks north of King St. being the same house in which Thaddeus Stevens died.”