Hi,
For the 66 years of my life, my dad has been Paul F. Henderson, Jr. My grandfather, his dad, was Paul F. Henderson, Sr. My great-grandfather, who was born William Gill in Faribault Minnesota, took the name Edward Francis Henderson sometime after he rode from Faribault to Ft. Leavenworth, where he first enlisted (and then remained as a soldier in the garrison for 20 years).
His name change decision has no available public explanation. But the facts are certain.
See https://www.findagrave.com/memorial/48278352/edward-f-henderson.