Have you found where John & Izetta were buried? Since they both died before Gusta, John in 1949 and Izetta in 1947, maybe there's a family plot in Detroit and if you're lucky, she might be buried with them. I know that there's a Detroit specific Death Index available only at the Detroit Public Library but they do accept look-up requests on an individual basis via e-mail. You have to do a bit of research to see what years are covered or ask. I used this e-mail address a couple of years ago; bhc@detroitpubliclibrary.org. The library also offers a list of researchers and I'm guessing they probably charge. Right now there's a website issue but you could also try using the search engine at; http://www.mtelliott.com/genealogy/. That site covers 5 major cemeteries in the Detroit area.

Good Luck & SISU!
ps I ALWAYS use a maiden name when using familysearch, as the father's surname and leaving the woman's surname blank. Also, the use of an asterisk(*) has helped me many times. You can use it for any amount of letters, at the beginning, in the middle or at the end of a name.

I noticed a slight error in the info you posted. Gusta married Alonzo in 1923 in Onaway MI. It was the third marriage for both of them. If you are using www.familysearch.org to search for records, you can find their marriage using the names Alonzo B Bessie and Gusta Wright. Their 1930 census info can be found using the name Alonza Benie, also using familysearch.