I have just begun to search my relatives and noticed your request of about 3 yrs. ago. I hope you have obtained the info you were looking for and maybe I can add a bit to it.
Gust Spielvogel (12 Oct. 1862 to 29 Dec. 1932) was a brother to my grandfather, Richard George Spielvogel of Manchester, Green Lake Cty, WI. Gust & Louise Ida Haas had three daughters: Laura, Mayme & Rose. I do not have birth or death dates for them.
Rose had a son, Roy Wilbur Spielvogel, apparently out of wedlock. As you state, the father was W.H.Harris, I think he had a dance orchestra. Roy also had an orchestra under the name of Roy Stevens. Roy married Alice Buschman of Sheboygan, WI. she was member of the Chordets, a gals barbershop group that was quite popular in the 1950's and appeared on TV, made recordings, etc. They had a son Roy Albert and daughter, Cary.
If I can help further, contact me at: firstname.lastname@example.org