Correction from a post I did some weeks back theorizing about the possible origins of the KTXL/WRAL early 80s music package: Cascom most certainly did not do the WRAL 1982 animations. I was re-reading a Millimeter back issue in my personal collection, and was reminded that I had already seen stills from the WRAL '82 animation package in an ad for Bill Feigenbaum's studio (which was based in NYC). Just wanted to put that here.
As to that WTVX package, I still think it could have been done in Dallas. (KHTV's music image package in the "39 Gold" period - which, as you say, didn't have corresponding news music - also sounds to have been done in Dallas. I swear it sounds like the late Chris Kershaw on solo vocals, but whether it was done by JAM, or he did it independently, I have no idea. Also I don't think I've heard a version that wasn't camcorded off a TV, as most of the YT clips I've seen of that period were.)