So, checked the power connector pins on the MB with a magnifying glass rather than just naked eyeing it as I did before, still don't see any cracks even when I try to move the pins with my fingers. Still, broke out the leaded solder and the soldering iron and reflowed and added a bit of fresh solder, checked to make sure nothing was bridged, it all looked good. Took it back upstairs, connected power, flipped the switch and...got the beeps on a cold boot.
Put it back in the case, connected the monitor and keyboard, let is sit for 10 minutes, and a successful cold boot.
Thank you for the help everyone