The exhaust leak was simply a loose bolt! I was able to track down by using a shop vacuum (hose attached the the vacuum exhaust so it worked like a blower) duct taped to the tailpipe and feeling for whooshing air near the engine.
I can say definitively the starting issue is the starter due to heat soak and I'll be replacing that soon. Starts great but hard to start (you have to jump the battery) when warm. Let the engine cool down 30 minutes and no issues starting it again.
Ran into an interesting problem coming back from an offroad trip where the Bronco didn't want to drive more than about 45mph. Made it all the way home before I found chunks of the catalytic converter clogging the tailpipe.
Currently I'm trying to determine next steps. When I bought the Bronco the transfer case didn't shift so I replaced it with a 89 transfer case which required me to redo the driveshaft because the output shafts weren't the same. Then shortly after that I broke that driveshaft and had to have it redone.
The thought is the drive angle or something about the transfer case isn't quite backwards compatible so I'm working to crack open the old '88 transfer case and diagnose the issue there; suspect its a broken shift fork and/or chain. So that may go back on with the new driveshaft and see how that pairs up.
After that back to fixing the creature comforts, AC doesn't work well, passenger side window quit working, and never fixed the rear window buttons. I used a battery pack and lamp cord to roll it up and down; reversing which wire is on the positive terminal alternates up versus down.