DNA Testing: Descendant of Old Peter and Interesting Matches on GEDMatch

A documented descendant of Old Peter Skaggs / Martha has matched with a documented descendant of David "Long Dave" Bishop (son of John Bishop and Ruth Skaggs Bishop)/ Elizabeth Wolford and matched with a descendant of William Scaggs / Esther of Montgomery County, Virginia to form a triangulated group on GEDMatch.  What this means is that there's about a 90% chance that Old Peter Skaggs, Long Dave Bishop and William Scaggs had the same common ancestor.
This triangulated group is further reinforced by a second descendant of Old Peter also matching the persons in this group.  All four of these matches share a segment of DNA on their Chromosome 11 that belonged to a single common ancestor.  Who could that ancestor be?

Well, we know Long Dave Bishop was the documented son of John Bishop and Ruth (Elkins?) Skaggs.  Family legend says that a Ruth Elkins married John Scaggs, was kidnapped by Indians, then later returned to Virginia and married John Bishop.  According to several U.S. censuses, Long Dave Bishop was born about 1781 in Virginia and later moved to Lawrence County, Kentucky in the neighborhood of Old Peter Skaggs.

We don't know who Old Peter's parents were, but there is plenty of circumstantial evidence (including these DNA results) that his mother could have been Ruth Skaggs Bishop, making his father the John Scaggs born in Kent County, Maryland in 1721.  Not the Zachariah Skaggs who died in 1818.  Not the James Skaggs, father of the Longhunters.

Here's the new information from this DNA triangulation:  either William Scaggs or his wife Esther had to be related to Ruth Skaggs Bishop, since we don't think the match to Long Dave Bishop involves Skaggs DNA.  We think the match is on Elkins DNA, not Skaggs since William Scaggs appears to have been too old to be Ruth Skaggs Bishops son.  William's only documented son, Joseph, was born c. 1765, meaning William was likely born in the 1740s.  Ruth wouldn't likely start having children in the 1740s and end with David Bishop in 1781.

My new theory is that Esther Skaggs' maiden name was Elkins; that she was a sister or cousin to Ruth Elkins.  That would mean the DNA that these test takers triangulated on is Elkins family DNA.  I want to caution everyone that this is just a theory built to match the DNA testing facts found from that triangulation on Chromosome 11.  Further research may disprove it, that's what research is for.