At ancestry.com (pay site) is your grandmother's Social Security record - she was born 23 July 1934 in Puʻunene on Maui, Hawaii, to Joseph Rego and Isabella Costa, in December 1954 known as Jeanne Louise Barnes, in March 1965 known as Jeanne Barnes Hardin, in May 1967 known as Jeanne Barnes Vanornam, in July 1968 known as Rene Reed, in October 1988 known as Jeanne Rego Elmore, in May 1997 known as Jeanne Rego Hardin. Died 16 December 2005.
At newpapers.com (pay site) there is a newspaper obituary for her mother from the Honolulu Advertiser of 5 May 1990. It states, in part: "Isabelle C. Rego, 85, of Menlo Park, Calif., died April 30, 1990. She was born on Maui and was longtime owner of the Hawaiian Gift Shop in Palo Alto, Calif." Among the survivors is her brother Anthony Costa.
At familysearch.org (free, but registration required) there is a family tree for your grandmother that shows her to be indeed descended from Portuguese immigrants to Hawaii.
As for the Hardins, I see that you have already entered information for Ochs Hardin of Indiana at familysearch.org (perhaps part of your inability to see your previous work here is that you had actually been working at familysearch.org rather than here).