Update: Problem is 75% diagnosed on my end of the line. For real this time.
I've figured out a way to determine each bone's exact, dead-on rotation relative to the actual model, as well as figuring out a way for it not to be a cluster of confusion.
Unfortunately, recent happenings have made my life significantly busier, so progress will slow on this. I'd love to release a tutorial on how to fix this but I'm afraid you'll all just want the fixed model rather than me explaining all my hard work... so it will be at least a month, but animations are on there way, everybody! :)
-EpicFrySauce