David, Good job. Although upon further research the Post Office at Recue, Mississippi located in Harrison County was started on March 4, 1858 and discontinued on July 6, 1860. The Post Office at Handsborough was established on September 2, 1856. the Post Office at Rosalee was established on May 18, 1854 and discontinued in the late 1860's. The Post Office at Red Creek was established on December 20, 1860 and discontinued on January 30, 1864.
I can't remember exactly what county you are helping in Mississippi but it might have been Kemper? According to the 1851 Post Offices the Big Oak Post Office was located in Kemper County. One of the Confederates who died at Camp Chase was Elbert Franklin with Company K of the 46th Mississippi Volunteer Infantry and listed his relative as Barbara Franklin and listed her Post Office as Big Oak, Mississippi. Using the 1850 United States census on ancestry was the following:
The 1850 United States census listed Elbert Franklin, born about 1831 in South Carolina and noted his occupation as a laborer and living in the household of Barbara Franklin, born about 1805 in South Carolina. Other family household members were: (Spelled as) Charner (A male) Franklin, born about 1829 in South Carolina and Julia Franklin, born about 1831 in South Carolina and Cain Franklin, born about 1835 in South Carolina and Ensley Franklin, born about 1837 in Mississippi and Mary Franklin, born about 1839 in Mississippi. The family household was living in Kemper County, Mississippi and the census was enumerated on October 18, 1850.
While there is a list of discontinued Post Offices in the 1851 Post Offices this is just a partial list within the vast collection.