Alright, y'all. The verdict is in. Apologies in advance for how long it took me (life and shipping delays got in the way)[br]
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It was in fact the long ribbon cable that connects the two boards together. (Thank you @devnol)
The unsuccessful troubleshooting I did prior was:
* Replaced the smaller board for the righthand buttons
* Replaced the power/volume ribbon
but ultimately was the long ribbon.
Thank all of you for all your feedback. I appreciate it.