in the future though you should run those gauges off a relay, culprit or not, I think 5 gauges will overload that curcuit
your short was back feeding voltage somewhere, thats why it stayed running w/key off
looks like you found most of the damage, but really the first step is to get schematics of each curcuit effected and go over w/fine tooth comb
also agree on using ohms on DMM to see if its short to ground w/battery disconnected