Not sure if this will help in your search, if not you may want to file this for future reference.
In my Hamann Family Tree files, I have the surname Leibetrau and have accumulated some siblings/parents surnames and dates of Oscar Herbert Liebetrau and his marriage to Viola Emma Anna (Hamann).
Your area of Greenbush is close in proximity to what I have of Town Mosel and Cascade, Sheboygan County. I would assume the Liebetrau's that I have would most likely be relatives/cousins of yours but do not know the exact connection.
If you would like my compiled information, please get back to me at rloss[a]bellsouth.net
Regards, Robert Lipprandt