How about the numerous online trees identifying Dorothy Lee Ray, mother of Billy Duane, et. al, as the daughter of Willard Dean Ray and Lee Nora Strickland? Online trees can be wrong, but the amount of information backing that up is enough to at least cause concern. As is your suggestion that Dorothy L. Ray (4 Mar 1926 - 27 Sep 1989) is Eula's daughter, though it is certainly possible she'd have taken back her maiden name between her marriage and her death. That's the thing - there are too many other possibilities. For instance, in your suggested route of looking for children born to a Dorothy Ray, there's a Gina Barton born to a Dorothy LYNN Ray, and in Bastrop County. That is absolutely plausible, especially given the fact that her parents were living in Bastrop at about the same time.
I'm far more willing to accept Fannie as being the one in Old Saltillo Cemetery - and, in fact, I'm going to adopt it as a strong probably - but I would still like to see some corroboration. No, I wasn't EXPECTING to find a death certificate, but HOPING. It's not there, and there could be many reasons for that. That doesn't mean that there won't be something else that supports the theory.
And, THAT, my dear, is "excellent researching."
BTW - Thanks for the offer on Glynn & Sara. I've found them, as well as Glynn Jr. and most of the other Stillwells. I was more anxious to find Eula, which you have helped me to do. Thanks again.