You can launch any program from command line, and if you pass --verbose you'll get more information (that's a common flag)
Thanks for the help! I FINALLY got the game to export to the web. How? I figured that if I made a new project and slowly copied each piece of the existing project to it, exported for web, test, rinse, repeat, that I would eventually find the piece that was causing the issue. Ultimately, I didn't. I moved a script or a scene, tested, and it exported to web. I did this until I finally had moved every resources/script/scene/asset and I never once got the error. It just works!
I'm really glad that it's working now, but I am disappointed in the fact that I still don't know what caused the issue. Since I didn't change anything, I just moved it all to the new project, I guess I'm going to assume it was some sort of freak Godot bug, but who knows. It's probably more likely that I did something wrong, I just wish I knew what! : ]
Thanks again for your interest and for helping me get to a resolution. The game is finally playable on the web. I also tackled the bugs that you pointed out. Cheers, @thePalindrome!