Following up on Neva Osburn's family...her death certificate lists her father as Sammy Osburn. In the 1930 US Census, Neva had married Lambros Gusetis, and she is the respondent on this census. She is living in Oakland, Alameda County CA (age 40) with Lambros and her son Carl Cowles; and lists her state of birth as Missouri, and father born in Illinois and mother born in Indiana.
I believe I have found her brother John Osburn (Osborne here) in this same census year, living in Shingletown, Shasta County CA (age 39) married to Meriam (age 38), they were ages 38 and 37, respectively, at their first marriage. They are roomers in the household of James C. Cowles and his wife Ellen. James would be the brother of Neva's first husband Joseph Willis Cowles. John Osborne lists his state of birth as Oklahoma, and both parents born in "United States".
So...if anyone has any information on Sammy Osburn, born between 1830-1870 in Illinois (I know that's a wide date range, but really have no other information) I would greatly appreciate it. Thank you!