Sedlak/ Ryant- Chicago

I am looking for information on a Sedlak family that lived in Chicago between 1881 and 1884.
Frantisek Sedlak immigrated approx. 1881 and landed in Chicago. He married a Annie Ryant in the Pilsen neighborhood. In 1884 they had a son Joseph born in Chicago and shortly after, they moved to Cedar Rapids Iowa. This is as far back as I have been able to go.
Ann lists her father as Josef Ryant and mother as Mary Krecji. Frank lists his father as Vaclar Sedlak and mother as Unknown.

I am trying to find that connection to the Chicago area that will lead me to where in the Czech Republic they may be from. I have been unable to make any connections.