I have no evidence that Fannie Mae Mauldin was from the same Mauldins that came from SC, but can only say I suspect she well could be.
You had asked about the "Hatley/Hadley" middle name. That got me to wondering & sort of sparked my thinking.
Starting back in NC, there was Edward Kirksey m. Rebecca Rickman, & had several children, incl:
Isaac Kirksey d ca1778 m. Mary ??? Isaac was the father of John, b ca1773d1850's, Edward, Isaac,& Sarah.
Just before Isaac died, he made a Will & one of the witnesses to Will was William Hatley,Sr.
There were Hatleys in the neighborhood, & Wm Hatley Jr. is witness on an Isaac Kirksey land deed, & a Wm. Hatley sold land to Christopher Kirksey, bro. of Isaac, & the Hatleys served in the same local Militia company as the Kirkseys in the 1770's, just before the Revolution.
This now makes me think that Isaac's wife Mary's maiden name was HATLEY, & this is why, if you follow my thinking:
Isaac's son John Kirksey is my ancestor & probably yours. So in John's line, going thru supposed son Bryant H. Kirksey to Ervin Littleberry Kirksey to your Irvin Hatley Kirksey.
Isaac's son Edward had probable son Isaac, b ca 1796, in Edgefield Co.,SC who had a son named Phillip Hatley Kirksey, who used his middle name as his 1st name & was called "Hadley" for convenience of speech, or to "soften" the "t" sound.
I haven't seen any signs of Hatleys coming into any other lines of families, so this is the theory I'm running with, & hope this answer is satisfactory to you. Thanks for making me do this homework.
In American Colonial records, I know of no documents showing Kirkseys beginning anywhere earlier than in North Carolina.
I don't know about the Hatleys, but looking at book "Colonial Soldiers of the South" which includes Maryland, Virginia, & southward, the only Hatleys listed are right there with the Kirkseys, around what is now Chatham County, NC., formerly Orange County,etc.
If you have questions, let me know. I chose to post here, instead of emailing you, in case any of this might be helpful to anyone else.
PS- Bryant H. Kirksey's wife, Lucinda W. Mauldin was b1797, in Laurens Co, SC & was dau. of James Mauldin & Mary Berry. James moved across river to Edgefield Co, where Bryant & Lucinda must have met as neighbors, before moving West.
The names Irvin,Irwin,Ervin,etc are interchangable spellings for male names in this family. I don't know if this is a surname that became a 1st name in the family or not. I'm still working on that question.