Found this on the genweb page for Voss, TX:http://freepages.genealogy.rootsweb.ancestry.com/~jrterry/co...
"In the early part of 1904, Voss was established; a part of the William H. Day ranch. When Mrs. Day decided to colonize her ranch, her location for the first settlement was Voss. It was named after her business manager, Will Voss. He was needing the services of a post office, so he sent in several names to the Post Office Department in Washington, D. C. His name suggestions had already been used by others, so the department assigned his name, Voss, as the one to be used."
So it was Will Voss, Edward's younger half-brother, later found in Miles, Runnels, TX, who was the business manager.
Don't know why some places call it the Leaday ranch, it seems to be called the Day ranch, after Mrs. Day. Maybe a mix of Lady Day Ranch?
EDIT: Just figured it out. Mrs. Day's second husband was a LEA. Not sure how, but it seems obvious that LEADAY is the mix of both of her married names.