Well, there's really no comment to be made, but that won't stop me :)
If the fact that Maria (Van Sicklen) (Linington) Freer was not available to be the mother of these Van Siclen/Lawson descendants is not enough to dissuade them, I 'm not sure what else is to be done. You have documented the case well for those who care to approach the situation using modern and proper genealogical method.This, of course, requires some understanding of the Dutch culture, including the naming conventions, the translations from Dutch to English spellings, etc (Annetje can be both Anna and Hannah, for example). I may have missed it among all the calumny, but I did not see any recognition of this by your adversaries. The obdurate refusal to look at the Lossing/Lawson (et al) article in the NYG&B Record you cite--one assumes this has not yet been read as there is no retraction of the unfortunate characterizations made against you in this matter--signals a general disregard for scientific and scholarly method in genealogy.
(Just between you and me and as a matter of curiosity, since the step-daughter of Catherine Johnson, Maria Van Sicklen, had children by her first husband Samuel Linnington and children by her second husband Simon Freer, perhaps she shows up as a baptismal sponsor for some of her grandchildren during the time she was supposedly married to Eastling?)
Regarding the testimony submitted by Violet Voorhees, it is an unfortunate miscue to these descendants that Catherine Johnson's names was used incorrectly.I agree with your assessment of how this error was made. But it seems to me that even though we accept that they descend from the Cornelius Van Sicklen who married Catherine Johnson, it is clear that said Cornelius VS had no daughter Maria by Catherine. Though Cornelius' will makes this point, as you cite, we also have the testimony of Catherine Johnson's blood-grandson by Cornelius Van Sicklen, Henry Van Sicklen (with a "k"), to noted genealogist Teunis G. Bergen in the 1870s--well before Ms. Voorhees' effort to join the DAR and without such a motive.
As for the bible record produced by Violet Voorhees, it should be said that it is a mis-characterization to state that the Notary was swearing to the truth of the entries. The Notary was only attesting to the fact that these entries were made in that bible. From what I have read in this thread, this Notary was incredibly conscientious in his duties--but there is simple no way that he would or could know whether the entries themselves were true. This is not to say that the entries are not true, only to say that the Notary was not saying that they were true--just that they were there and said what they said, within his ability to decipher them.
Lastly, it might be interesting to see if any of these descendants would be allowed into the DAR, SAR or other like "patriotic organizations" based upon the submissions of Violet Voorhees. Their standards of proof having been vastly improved since the turn of the 20th century, I think not.