You mention son as Jacob born 1716

I've got a will from Charleston SC belive to be this Jacob Harrell as have always been told his father was Francis Harrell of Nansemond Co VA who owned line in that area as early as 1734 and that Jacob born prior to this date.

The will mentions his spouse is living and he wants her to have use of the house and land which he leaves to his Grandson Levi Harrell, Jr. Also listed in this will are his children with their married names that match what have always carried as his. Also his Son Levi, Sr, is named as Executor along with Silas Simmons spouse of his daughter Selah (Harrell) Simmons.

Other children listed as follows in this will dated 22 JAN 1787:
Note there is nothing telling when he died as this is only a will being recorded at this time by him.

Levi Harrell
Leacy Barfield
Selah Simmons
Ann Simmons
Martha Curtis
Mary Black
Jasper Harrell

Above are to sell and divid the estate only if his spouse not living

His son Lewis only gets 3 guineas but has already recieved something prior and it's to be his free and clear.

Levi Harrell, his son, and Silas Simmons are Executors.

He, Jacob, made his mark as did Samuel Tindall and Selah Simmins while a Levi signed the will (this was the son as Levi, II born 1777 would only be 10)

Also got will of Silas Simmons that clears up if Ann or Silah is his spouse. This will dated 27 FEB 1795 names Silah as his spouse (due to reading of name as typed in a reprint of older records in 1938 her name is seen as Lelah because of way letters S F L written by folks at this time)

His, Jacob, will was from Book B (1786-1793) Page 83
Now in Book 22 (1786-93) Page 119-120

Silas Simmons was from Book C (1793-1800) Page 237
Now in Book 26 (1793-1800) Page 346

All found in Charlleston SC records.

If any actual documented proof of a link between Francis and Jacob is around please let me know where it can be found. As I know that Nansemond Co courthouse has burned down at least three time and all records before 1800 have been lost to them....