As a point of note, in 1817 there was no Tangipahoa Parish/County in Louisiana, but people do refer to it as a region, as the Tangipahoa River runs through the area.

As to the Varnado's, I'm descended through Samuel Varnado's and Sarah Newson's son Samuel. I have seen no reference to a Moses in my research, but I'm only just beginning my research, and I may just not have found it yet.

There are other common spellings of Varnado. According someone elses research I ran into online, there are currently eight spelling variations currently in use, and at one point there were as many as 32 (I wish I could remember where I found that). My mother remembers the spelling/pronunciation Varnadore being in use in Louisiana, and one ancestor I've traced it to, as well as said ancestor's father, used the French spelling of Varnadeau. You might want to check under these as well. It is also possible to replace 'Varna' for 'Varne' and get the same pronunciation. Like I said, there are several spelling variations.

Let me know if I can be of more help.