You said: "I have a connections with The Tilghman/Tillman family who married in the Abernathy family."
That Tillman-Abernathy connection is a persistant and sore point of contention. The supposed fact that Christian, daughter of Susanna Parham later Tillman was in fact daughter of Susannah's 2nd husband Roger is far from proven! I, personally, doubt it very, very strongly. And have said so in this forum before. There is not an iota of evidence in Susannah's will to establish the maiden names of any one of her three daughters nor prove which of her husbands was the father of which daughter. The supposed facts of her will that are said to confirm the problematical theory that Christian Abernathy was Roger Tillman's daughter have absolutely *NOT*, in my experience, proven to be solid but more like smoke, mirrors, and an inept stage magician's attempted slight-of-hand tricks! Not, in other words, to be trusted. Yet silly fools continue to believe it. Hogwash!
The very early and entirely unsupported Abernathy-Harwell/Harrowell connections in the 3rd & 4th generation of Abernathys are yet more foolish beliefs by those who are themselves inept and persist in equating suppositions and half-baked theories with provable facts when they are anything but.
As for Lucy or Lucinda's marriage, I have not a single shred of evidence to substantiate that, and do not believe that she is found anywhere in the deeds or tax evidence of the settlement of David's estate at all. If you wish us to believe your claim that she married someone named Robertson it's up to you to provide documentary evidence from her lifetime that can be verified by independent researchers.
In my view, if it can't be independently verified via contemporary records from the person's lifetime, then it is little better than a warm fuzzy myth or a fascinating but unproven theory.