Looking for census records would probably be a good next step, if you haven't already located them. So for example, since it looks like you know John Jackson Cochran's birthplace (Washington County, Pennsylvania) in 1911 and his parents' names, I'd look for his parents and siblings in the 1910 and 1920 census records in Washington County, Pennsylvania - the family should be listed together. That should give you at least a birth year and birth place (usually just the state). That information may help you locate their birth, marriage and death records and/or obituaries. Census records and a lot of other records are available for free on familysearch.org. Good luck!