There were two pieces of the puzzle that needed to be investigated:
(1) The 4 known burials of the Holloway extended family
(2) The newly found burial of a Holloway child (from Rev. Ebenezer Parkman's August 1738 diary entry)
The shared surname indicated that there may have been a close familial relationship and that families did desire to be buried together.
Further investigation found that the Holloway child was the grandchild of Adam Holloway (the oldest of the remaining stones in the Brigham Street Burial Ground). Adam's son William had at least 8 children, all born before or during the years the Brigham Street burial site was officially active (1727-1749). As for the exact identity of the child who is buried there, additional research needs to be done, specifically to document which children died on or before Aug 1738. To date, I have a record of one childhood death, that of William Holloway, Jr. (1726-1727).