My file on Robert "King" Carter is
www.multiwords.de/genealogy/Ct9RobertCarter.html
My maternal grandmother's Nicholas line to him, his mother and her Ludlow family of Hill Deverill as earlier included in the 17th century Heralds' Visitations was registered at the College of Arms in 1974 on the basis of primary documentation (certified copies of wills, deeds and other contemporary documents. No secondary documentation such as publications accepted for such registration.) The College of Arms drew up a pedigree of the Ludlows going back to King Alfred the Great and Charlemagne and sent it to me. When I began putting my 3000 or so pages of hardcopy genealogical research into digital form in January 2006 I googled with all loose end names, which brought in endless avalanches of data from thousands of unauthenticaed sources on all possible branches of my ancestry and as many collateral lines as possible, which I have pieced together in about 5000 website pages. From 2009 on Y DNA and mitochondrial DNA matches and descent lines.of my matches have been noted in these files From 2012 on autosomal DNA matches have been noted.
No complete and authenticated data on Robert "King" Carter's children was available in the internet for a long time, nor on his siblings nor half siblings, nor on his first, second and third cousins, nor on any of their descendants. But in time I have been able to round out the picture, allbeit from hearsay not authenticated.
Robert "King" Carter amassed 7 plantations and 1000 slaves in his lifetime, married twice and had 16 children according to what I have pieced together. He may have had children by other women as far as I know, but I have no such credible report besides those being discussed for his first daughter Elizabeth.
Her second marriage to Dr. George Nicholas has not been documented yet, nor have the exact dates of birth of their three boys. But Robert Carter Nicholas seems to have been born first and after 1725. Elizabeth seems to have died before 1732 and Dr. George Nicholas by 1736.
My mother's first cousin, Brig. Gen. Charles Parsons Nicholas had had access to governor's communications with regard to the family in this period before he passed away in 1976, But I have no details.
The three reports on Leannah Nicholson obviously all have guesstimated dates of birth and only the one for 1750 lists the three Nicholas boys as half siblings, which to be true would mean Dr. George Nicholas would have to be her father and that she was born by a different common law wife to be true.
There are perhaps branches of the Nicholas family that took the spelling Nichols. The name Nicholson is doubtless a patronymic derivation for a son whose father was name was Nicholas, whether first or family name is an open question. But in Wales they generally did not have family names and every son got the Welsh patronymic form of the father's christian name. Whenever a Welshman moved to a town under English administration he was stuck with the English spelling of his patronymic as a family name for all his children and theirs. The spelling was pure guesswork for the English official who may have had to do his best are being subjected to a heavy Welsh accent, that a literate Welshman surely would have written differently. Just as the American speelings of many a German or Polish name has been trimmed to fit English phonetics.