I know yours was an old post but there are a few points I want to add. The Wells DNA testing does indeed show a relationship between John Allen Wells and the brothers William and Jonathan, however that relationship is more like a cousin or a step-brother. William and Jonathan have a 1 marker difference and John Allen has a 3 marker difference. The Obituary of William Wells Jr only names William and Jonathan as part of the 5 sons and 3 daughters that came from PA.
There is a biography of Rev. Amariah Biggs that married John Allen's daughter Mary that says she was the granddaughter of the Rev. war soldier William Wells. With the DNA testing we know it's not the William Wells that married a Westmoreland:
A BIOGRAPHY ON REV. AMARIAH BIGGS, M.D.
After her untimely death Dr. Biggs married Miss Mary Alva Wells (born May 27, 1820) on December 1, 1838 in Tennessee. She was the granddaughter of the respected Revolutionary soldier William Wells who suffered Valley Forge with General George Washington.
[There were two William Wells at Valley Forge. One from VA and one from PA. William Wells from VA married Sarah Westmoreland in 1786. DNA results prove John Allen is not related to William Wells and Sarah Westmoreland Therefore he must be from the other William Wells from PA. This would make sense since he is related to William and Jonathan Wells who are from PA.]
The evidence for the Morehead surname comes from a letter written by Melinda L. Laughlin[granddaughter of Henry Livingston] in 1899. In the letter she talks about her family:
"My grandfather LIVINGSTON was in the revolutionary war. After the war he went to Kentucky and was married to a young lady by the name of Morehead." Also while not evidence of the name it is interesting to note that in the Providence Twnshp census of Bedford county, PA in 1783, 4 and 5 Henry Livingston was living next door to John Morehead.