My replacement motherboard came in today, just got it installed and working. So far no problems. Going to run memtest tonight while I'm unconscious and vividly hallucinating for hours for some not entirely understood purpose.
It looks like everything is working well now. I just wanted to pop in the thread and thank you. I don't even want to know how long it would have taken to get this all figured out and taken care of. Thank you for your patience. It's incredibly impressive how many people you help on this forum.