Alvina Doering is also listed in the 1910 census of Wausau as a widow. She is listed in the city directory for 1927, but doesn't seem to appear in the 1930 census. Herman appears in the 1903 city directory. Alvina appears as his widow in 1912.
According to familysearch.org Hermann Albert Döhring was married to Aliornce Friedrike Wilhelmine Zastrow on April 6, 1888 in Marathon County. His parents were Friedrich Döhring and Dorothea Trabanl (sp). Her parents were Carl Zastrow and Caroline R...Sch (sp).
This is from extracted data rather than from the record itself so the spellings may be off. You probably can find more on this family at this website which is free.
Herman was probably born circa 1848 rather than 1878.
If you know where they are buried check with the cemetery office to see if they can help you. If you don't know where they are buried you could check with a local library or historical society to see if they can help you with burial place and obituaries. You might also try to get their death certificates through the Wisconsin Heath Department: http://www.dhs.wisconsin.gov/vitalrecords/genereq.htm#G4http://www.dhs.wisconsin.gov/vitalrecords/genereq.htm#G4
The death certificates should help confirm who their parents were and will list where they are buried.