Did you intend to post on "Henderson Surname Board" vs Henderson County, TX? No way will you solve this "brickwall" online, sorry! I perused birth certificates of the twins, Haskell and Harry, several times without deciphering their mother's maiden name. Still not certain, but it is definitely not "Falter" as interpreted by https://familysearch.org/
It is more akin to Tolter/Talter/Taulter as enumerated in 1900 TX-Cass-Precinct 3-District 0023-Image 10 for the family led by Sol Taulter. Ora Tolter wed Harvey Houston 2 Jan 1904 in Cass County and he must have been husband #1? FYI, this family lived in Bryans Mill of Cass County and that's probably closer to New Boston than Linden (Cass County Seat)? Found marriage record for Walter Henderson to Ossie May Heard on 22 Oct 1928 in Miller County, AR. Don't know what happened after the marriage 'cause Walter was boarding with the family of Jasper Reid in 1930. Ossie found, prior to marriage, in 1920 Camp, TX as daughter of Caleb.