The Lillard line in the 18th century is indeed a mess. My great-great-grandfather Thomas Madison Lillard is certain and his father Thomas Lillard probable. Thomas Lillard's father becomes more dubious - see Lillard-56. In the notes on at least one of these Thomases, I have mentioned the difficulty. I assume that the line preceding Lillard-56 is accurate, with the Benjamin forename reappearing in my maternal grandfather, Benjamin Lillard Hargis, though indeed that could also have come from his non-Lillard grandmother's family as his father, Benjamin Finley Hargis, had it as well. Please follow what I've done with this line in case it could be any help. I would appreciate anything you can come up with to provide more clarity.
Best wishes, Stoddard (Chip) Martin