Biggest technical lessons to fall out of this:
* RTO club is 0/2 on reflows but 8/9 on reballs. I would have expected reflows to be less risky than reballs, especially when done by someone without prior experience, but the numbers argue heavily (as heavily as they can with small N) for the opposite.
* Check the resistances of your main power rails before you apply power. Write them down before your reflow/reball and check them afterwards. Save yourself some trouble