DarkSkySeeker wrote:
About an hour later, mysteriously, they were on.
Here's the real guesswork...
The contacts on the old breaker looked bent. While on there was continuity but I could not tell if power was getting to it through the bent contacts.
The mysteriously turning on an hour later sounds like a loose wire connection. I would kill power to the entire trailer, and then tighten every single wire in your panel.
You just installed a new breaker. But you were not able to test the old breaker, or the new breaker? Be careful but just flip the breaker on and probe the screw and the neutral bus bar. If you see 120v, the breaker is working.
While i think its a loose wire you could check where your fridge plugs in. That might be an outlet that you have not checked for a gfci yet. But.....its almost silly to consider the GFCI to be the issue since power resumed on its own.
I would first find the neutral that is used for the new breaker you installed.