As far as I can tell, you haven't even proven your lineage back beyond the 1850 census, Otis. You just think you have. But you keep avoiding picky little details that might dispute your case, such as the fact that the 1840 David you think is yours doesn't (in 1840) have a wife the proper age to be your Jane, who shows up in 1850. And that the census tallys for the 1820 David in TN and the 1830 one in Al and the 1840 one in Al simply do not track well enough to be sure that those are, indeed, one and the same individual. And you haven't even begun to account for the daughters or extra sons that show up on those tallys but which you keep ignoring.
As for the 1820 Joseph found in Giles County TN in 1820, it appears to me that you are extrapolating from wishful thinking and thus doing exactly what you are warning others of doing: muddying the waters most thoroughly.
You have yet to produce contemporary evidence (ie, public records from the time in question that clearly shows linkage between one individual of one generation and another individual of the next. Wills, estate records, pension depositions, deed transfers, and the like.
From the 1850 census onward, your evidence is better, but still sufficiently vague that I cannot imagine a reputable and certified professional genealogist putting their reputation on the line by stating what you have claimed as regards your pre-1850 lineage. There's too much missing evidence.
Prior to 1850 you simply have yet to demonstrate that the Joseph found 1820 in Giles County TN is the Joseph found Lincoln County NC 1810, or the Joseph found Lincoln County NC 1800, or the Joseph found Lincoln County NC in 1790, or another one not found on any extant census record. Nor can you demonstrate beyond a shadow of doubt that the Joseph found in TN in 1820 is indeed the son of David Abernathy whose will mentions a son named Joseph (whereabouts unknown when the will was executed). Even the age of that Joseph is not an irrefutable fact, since tradition cites him as being born abt 1749 in Bristol Parish Virginia but that alleged fact is emphatically NOT substantiated by the extant records of the Birstol Parish Vestry Book and Birth Registry, nor by any other historical document of which I am aware.
And surety on a marriage bond does not positively prove that the bondsman was in any way related to either party, despite the number of times that it happened they were, no more than proximity of names on a tax list proves blood relationship of the individuals in question. Neither is a stand-alone fact proving relationship, as a birth certificate (or church registry) would be.
Simply put, you have not provided for our edification enough SOLID historical evidence yet to make a determination as to who's who. Even if it does turn out that the Joseph in Missouri wasn't the one who really was the son of David Abernathy Sr of Lincoln County.
Until you can provide more irrefutable historical evidence, perhaps you'd do well to heed your own advise, and not be quite so quick to chide others so strongly for unwittingly doing that which you, yourself, have, in all apparent ernestness, done much of in the past (information you now disallow) and which you may still be doing, however unwittingly.