I have been trying for some time to unravel these "Harvells" with only mixed success.
I am working with the assumption that they are all "Harvells" and not "Harrells" but am not totally convinced of that. From my research it is also distinctly possible 2 distantly related Harvell lines are living near each other and interacting with each other.
In particular I believe all of the 22 Har**lls on pages 325 and 326 of the 1850 Coffee County census are "Harvells" and there is a probability the 2 on page 271 ("Susan Harroll" and "Delithia Harwell" are also the same family. I am less sure about those listed as Harrells on page 268. There is a distinct possibility there are Harrells living close to Harvells just to make life difficult. The Hopkins family is found on page 326.
In later days all of the lines I can trace from this general vicinity use Harvell or Harwell or Harvill as a surname but I have not traced them all.
This family group appears earlier in Pike County, AL in 1840. They are associated with the Taunton and Tillman families in several locations. Some information I have indicates they were all involved with the timber and turpentine industries and as such moved around a good bit (without leaving records of land ownership).
In 1820 this Taunton family was living immediately adjacent to Elijah Worthen, Sr and wife Nancy Holladay in Washington County, GA. Nancy Holladay Worthen was a half sister to the six children of John Harvell who died in Cumberland County, NC about 1767. His widow Margaret married Ambrose Holladay and the whole extended family moved to Georgia shortly afterward. In general the family used the Harville spelling in Georgia but all variations are recorded. I cannot trace with any certainty which Harvilles in the Washington, Columbia and Warren County records belong with which of John's children and grandchildren but it is apparent most of the "Harv*ll* and Harwell records in those counties from 1770 to 1820 belong to John's children and grandchildren.
A search of the various bulletin boards (Harvell, Harvill, Harville, Harwell) using combinations of terms such as Cumberland and Holladay (various spellings) will produce a myriad of postings.