The wonders of diagnostic applications and being ugly and not having everything fully hooked up. I was iffy on the Kalman filter pulling out correct values but as soon as I talked with Filpe Varela, the original coder of the Kalman filter implementation I'm using, talked me through some of the values and wtf they actually meant, I think I got it! Once I tuned in my accelerators, the angle estimates started working properly. In doing this, my headache magically disappeared too.
I actually only need the angle estimate for the X axis too.
I will say doing code with magic numbers, not so much fun but when people help out you, makes life so much easier. Thanks Filpe for the email response! Once I track down what the last few numbers I'm not sure on actually mean, I can tune in this mofo perfectly.