I'm a fan of your videos, I have gone thru many different 4L60E transmissions they dont hold up well. Trans heated up burned up the bands you'll be shocked now but yea like everyone let's you know itll fail soon. Good luck keep up the vids.
Definitely need to check the fluid in that trans! I'm assuming that was the first thing that you would do? Drop the pan and put in a new filter kit and fluid and it will be all better! Water and heat clogged up the filter and makes it not able to flow right and u had it under water so it has water in it for sure!!!
The Bronco you posted is sweet as hell. I love the older SUVs that have removable tops. You should totally get the Bronco and restore it and make it a really nice truck inside and out. Would be way cool to watch that build series.
When you take the carpet out you should do some sort of rubber lining on the floor to prevent any further water/mold damaging anything and you should totally seal it up and seal up all the electronics.