Just posting a little update on myself, hoping someone might read something and remember something and then say something.
I was flipping through the Mansker site, poking around to see if I could find someone else telling an old family story about land between Poplar Bluff and Puxico that was lost in a card game, when I ran onto the Arkansas Marriage Records page.
That lists a Lute Mansker marrying a Rosie L. Davis in 1911, which I think fits too well to be just a coincidence (not that it matters much, as Lute is marked as a Missing Mansker himself). In response to the year listed, my mother points out that great-uncle Delois, oldest of William Luther and Rosalie's children, said he was too young to fight in WWI (1914-8) and too old to fight in WWII (1941-5).
Again, if that sparks anything for anyone, if anyone can offer any help, I'd be much appreciative. :)