I have some preliminary information that I can give you, taken from information online. However, with a bit of good fortune I may be able to fill in the blanks for you and Susanne, after I get to the library.
From the 1930 Ithaca, Tompkins, NY census we know that Ina was born ca 1891 in IL. From the 1925 Iowa census we know that Willfred and Ina then lived in Adel, Dallas, IA so I thought it appropriate to look for Ina in IA.
1900 Cedar, Fonda Town, Pocahontas, IA, STRAIGHT family:
head, Lee L., 39, b Dec 1860, md 18 yrs, IL NY PA, propreitor-brick and tile works
wife, Ida M., 39, b Apr 1861, 6 chn, 6 living, IL OH OH
son, Halver R., 15, b Aug 1884, IL
dau, Fleda D., 13, b Sep 1886, IL
dau, Gladys L., 11, b Dec 1888, IL
Ina Lue, 9, b Feb 1891, IL
son, Merton T., 6, b Jan 1894, IL
dau, Alma L., 1, b Oct 1898, IA
Lee S. STRAIGHT and Ida M. TANNER were married 28 Dec 1882 in Livingston Co. IL. (Record is in volume G, page 1498). Since there is no census available between 1880 and 1900, one can only presume, until proven otherwise, that their first 5 children were born there. If you care to persue their births, check the info available for Livingston County at http://www.ilsos.gov/GenealogyMWeb/IllinoisRegionalArchivesServlet/http://www.ilsos.gov/GenealogyMWeb/IllinoisRegionalArchivesServlet/.
In the 1910 Fonda Town census the family is intact less Halver. That census also shows a daughter, Galen L. age 26 but the actual page looks like "Gadys" or Gladys.
In the 1920 census, still in Fonda, only Lee, Ida and Alma are in the household. In the 1925 Adel, Dallas, IA census,only Ida is living with her son, Halver, and his family. Lee Smith STRAIGHT, d 24 Jan 1922 at age 61. He is buried in Glendale Cemetery, Des Moines, Polk, IA.
in the 1930 Toledo census, Willfred was listed as living at 4022 Walker Avenue but his name is crossed out. The notation looks like "placed on non resident ?". My guess is that he was in the process of moving and would be enumerated at his new address.
Lucas County real estate records show that 4022 is now 4020 and is a 1905-built 3-bedroom duplex structure. Perhaps, Willfred considered buying it or rented a room there and was moving out when the census taker arrived. Personally, it now looks a mess!
If Willfred died ca 1951 he won't be in the OHDI at Ancestry. That index only includes deaths 1958-2002 and the OHDI at http://www.ohiohistory.org/dindex/http://www.ohiohistory.org/dindex/ covers 1913-44.