Hope you have ordered Henry Ritterhof's military pension records (it will hopefully tell you where
he was born in Germany). Today, I will try to help on the Lenz family.
Based upon the following record:https://familysearch.org/pal:/MM9.3.1/TH-267-11784-111061-95...
Frank A. Lenz and Bertha Fritz were married on June 26, 1901 by H. E. Heyn, a Lutheran pastor in Adrian, Michigan. I presume Frank was the illegitimate son of Theresa Lentz as his father's name was not given. Bertha Fritz was the daughter of Charles Fritz and Henrietta Tietz. Frank was apparently living in Detroit and Bertha was living in Adrian. The marriage was witnessed by Arthur Stoebner of Adrian, MI and Augusta Schact of Detroit, MI. Likely, the witnesses are some relation.
It is important to note that this is a civil marriage record and not the church marriage record. I would highly encourage you to contact the Lutheran church in Adrian, Michigan and ask them for a copy of the original marriage entry as it was likely written in German and may contain further information such as where each person was born.
I also found Bertha's sister, Amelia (Fritz) Schultzhttps://familysearch.org/pal:/MM9.1.1/KF3B-CJY
I think you'll find the parents there in the census info and perhaps you will be able
to find their passenger list record. Or better yet their church burial record which may
list their town of birth.