In case this is helpful to your research, Milwaukee's German newspapers have wedding anniversary photos for a Robert & Ida (Henschel) Kunath in Nov. 1908. One paper does not include any biography.
Not too much later on, there are family death notices for a Robert & Ida Kunath. Robt. also had an obit. with a photo.
These are some of the 50+ Kunath and 25+ Kunath entries or references found in "Milwaukee's German Newspapers; an index of death notices and related items" (1844-1950).
Gary Rebholz, compiler/editor
Indexing Milwaukee's German newspapers continuously since 2007... helping family researchers collect evidence of our historic German-American culture.