I found a Barbara Oberholtzer Kilheffer on my tree married to a Rev John Herr Brubaker. His father is listed as Jacob Nissley Brubaker and mother as Anna Hosetter Herr. This is from Family Search. Since some or all of the children are listed with the middle name of Kilhefer it would customarily mean that was her maiden name but I suppose could mean it could have been children to her first marriage. I have not researched all these possibilities.
If I start with my husband's grandmother Emma Hershey Hoffer 1884-1950; her mother Fannie Brubaker Hershey 1858-1935; her mother Mary A Brubaker 1835-1903;
Jacob Brubaker 1803-1886 ; the 7th hreat grandfather is Hans Jacob Heinrich Brubaker 1631-1725 maried to
Susannah Meyer 1668-1730. If this is helpful and you would more info, please let me know. I have found so many people with the same name as you have found. I will be happy to receive your report. June Gibble