There was a student named Olivia Brickell on the rolls at the Mordecai school, for one year (1817). She was listed as being from "Washington," with a Slade Pearce attached to her name in the February 1817 ledger entry. (Not the child actor Slade Pearce, though I suspect the identical name may bring some traffic here from disappointed fans. Sorry kids! This Slade Pearce seems to have had a tin factory near the Bridge in Beaufort County, and had a noteworthy library too. He was also Beaufort County sheriff a few times between 1807 and 1817.)
An Olivia Ann Brickell was named in legal documents with a Mirina Brickell, and as a co-heir to Slade Pearce of some land in Beaufort County NC.
Also at Washington, Beaufort County, Olivia A. K. Brickell and William Ellison married in January 1829. She is described as the daughter of the late Mr. Benjamin Brickell. A Benjamin Brickell (1773-1812) was a member of the State Senate from 1809-1811, from Franklin County (closer to Raleigh than coastal Beaufort County). His sister Ann married Dr. Hill and lived in Warren County (where she was apparently friends with Caroline Mordecai Plunkett in the 1820s). But he's listed in a Brickell family Bible as having only one daughter, an oddly-named Benjamin Ann Brickell. (Perhaps that girl's name was changed after Mr. Brickell's death in 1812, but before she attended the Mordecai school in 1817?) This Benjamin Brickell also had a sister Marinia, b. 1777, who might be the Mirina in the documents mentioned above.
A William Ellison was the land entry officer for the County of Beaufort in 1820, and a county clerk in 1833. This Ellison family tree has Olivia Brickle married to William Ellison.
But still.... no firm story here. What was Slade Pearce's connection to the Brickells and Ellisons? How old was Olivia when her father died, when she went to school, when she got married in 1829? Was Olivia once "Benjamin Ann"? Feel like I'm looking at the right people but not finding anything much to put together about Olivia Brickell/Brickle Ellison(?).