Welcome to WS WingedAtrocity! Quite a bit of effort has been spent on this case, and I'm not sure what you could do from San Antonio that hasn't already been done.
The person who last spoke with WCJD reported that WCJD claimed to be from Aransas Pass / Rockport Area (i.e., near Corpus Christi). She was probably lying, but I would want to look into it nevertheless.
I'm not suggesting that you drive the 150 miles to Aransas Pass, but the one thing that I would do if I lived anywhere near there, would be to go to the local High Schools and Jr High Schools and ask them if I could browse through their 1979 and 1980 yearbooks. Classmates.com has recently started putting yearbooks on their site, but they haven't yet added any from Aransas Pass High School.
Maybe Law Enforcement already though of doing that, but if I ever was in the Corpus Christi area, I probably would do that. A couple of hours at the Aransas Pass HS would be nothing compared to the hours I've spent browsing through MP sites.