Just an update, I played the first campaign mission again and it worked this time, and to be certain I saved the game at key points.
This time, after the victory screen that displayed the statistics, the game crashed and so I sent a crash report with my email tagged on it. After I reloaded the game, it seems that thankfully the Xendar campaign has been unlocked, so I will continue the story. I have several associated saves uploaded in a folder called "latest saves"and should work on the link from my first post.
Just to be certain my computer isn't the culprit, I ran it through multiple torture tests of Cinebench (several hours at a time for days), Intel burn-in test (1 hour, standard and high), and also ran hours of Memtest86 at boot time. I also ran Winrar benchmark up for hours and did a smattering of other less intense tests (folding@home, etc) for another period of hours. No errors or blue-screens were recorded and everything has been stable, running fresh Windows 10. That being said, these tests have been running since last week as I have been running unrelated cooling benchmarks to take advantage of the currently freezing weather here
System (might be helpful):
Intel 5820K, Asus X99 Pro, 48GB DDR4-3200 (G.skill, Triple Channel), Samsung 860 Evo 500GB x2 (RAID 0), Asus RTX 2060 6GB.