I'm on the verge of analysis paralysis!
Yep, welcome to PondBoss.
In a pond intended solely for food production during a survival situation, I would want species and strains best suited for my geographic location.
CNBG are a subspecies of northern strain bluegills. Either one would work in your location, but CNBG are often reported to grow faster than northern strain fish...a distinct advantage I might think. Of course, if the calamity involves a dramatic shift in the weather patterns, and Texas begins experiencing vastly colder than normal winters, well.....

I would probably go with a local, reputable supplier, who is familiar with the growing conditions in your area.
Personally, I would stock CNBG and northern strain LMB.