I'm sorry that I haven't answered you sooner than this.
I have gone thru my records and haven't found your August Zastrow, but
the Zastrow's certainly have a habit of using the same names. They seem
to love August, Friedrich, Bertha,Ella,Herman, Frank,etc.
Our Zastrow family are from Regenwald, and several of them did settle in
the Lincoln /Marathon county area.
If I come across anything that looks as if it would be of interest to
you I will forward it to you.
Happy hunting, Irene