[Splattj]

Is your 12v battery dead? If you jumped it but it's completely dead, the low voltage could make everything crazy. If it's a fresh battery, use a code reader to clear those codes and see what comes back.
How much metal are we talking on that T-Case? Chunks of gear or just sparkles? Was it magnetic?

 

[Splattj]

Why was the ETACS ECU swapped? Yes, they can be re-coded with a MUT tool at the dealer but it sounds like your dealership sucks and I know these days they seem to be increasingly hard to find. Buy a smartphone OBDII reader and see if you can clear the codes. If it's the ECU mismatch causing your problem, you'll need to find a way to get it re-coded. No affiliation or experience but: Check This Out

That is a lot of shavings on the drain plug! Does the T-case whine or make other terrible noises? If not, you can probably run it for a while or look into a rebuilt TRE or Shep unit. I've also seen them for ~$1,000-$1,200 used on Facebook