I think tht your "Odis Gage" may have became known as "Odis Mills".
The 1930 census shows him as "Odis Mills" with parents L.H. and Fanny Mills;and a brother J.H.Mills who is 15.
"Lewis Henry Mills" died in Tarrant county in 1937.
A "Odis Delbert Mills" died in Cleburne,Johnson Co.,TX Feb.11,1970; parents shown as "Louis Henry Mills" and "Sarah Frances Cole". "Frances" is most usually shortened to "Fanny/ie" by people of times, which makes me think she's "Fannie Cole". The informant on the death certificate was the brother, "J.H.Mills". The certificate says that Odis never married. He was buried in Rio Vista Cemetery-Rio Vista,TX.
Orma Gage is tricky; one thing I do see is: Orma D.O. Gage enlisted in the army on June 3,1902 in Dublin,TX; age 22y 11m;born Cherokee Co.,TX. He was a cowboy by trade, 5'11";brown eyes,dark hair. Enlistment shown as "Coast Art-105" which I gather means "coast artillary"and a unit #;he was dishonorably discharged on Apr.14,1903,Presidio,S.F.,Cal.-Presidio,CA?
Based on the birth place, if you are unaware of it-the son of John Thomas and Amanda Gardner Gage; there were 10 other Gage children-in Cherokee County in 1880; Nacogdoches Co. by 1900.
I think that Sarah Mills died at the age of 91- Dec.1,1971 in Hurst,Tarrant,TX;middle initial is "off",but could be a typo; parents given as "Jim Cole" and "Martha Sanders";certificate witnessed again by "J.H.Mills". She is buried in the same cemetery as Odis.