Dare I say it, its a wrap.
Without an optical drive, the stuttering and BSODs are completely gone. I've tried everything I can to get it to crash but have not been successful.
I'll keep running without an optical drive for some time to confirm then work on getting the optical drive back in. The problem must've been an intermittent connection between the motherboard and OD. The fault is likely with the drive itself, the cable, or the connector on the motherboard. Or maybe the ZIF connector was simply loose.
Strangely this isn't the first time I've experienced a stuttering issue related to an optical drive. 7 or 8 years ago I had a Sony VAIO that would hard stutter when downloading something over wireless or ethernet. After going through everything I could think of, I had run out of ideas. In an unrelated event, I updated the OD's firmware and the issue was completely gone. That computer still works well (but is quite slow now).
To this day, I don't know why this is so.
Updates to come...