Walker Co, TX was formed 1846, but I do not see any Flood listed in "Republic of Texas: Poll List for 1846", compiled by Marion Day Mullins.
Several Childress, but none in Walker Co, TX.
Green Stillwell -- Walker Co. John Stillwell -- Walker Co. H.J. Stillwell -- Anderson Co.
Have you checked the Walker Co, TX GenWeb site?Some GenWeb counties are not only putting their cemeteries online, but other info, too.Post your query, plus ask if anyone has a county history, and would they check for any possible info on your Walker, Stillwell and Childress lines.Being there that early, good chance there will be something in county history about them.