I wanted to let you know that Festool agreed to give me a new saw today, so I'm happy about that. I'm going to try it out tomorrow.
You could turn the saw blade on my old one by hand as easily as their demo, so I think that would indicate that there wasn't a stuck brake, but I'm no expert on Kapex repair. It doesn't really matter to me anymore what was wrong, I'm just hoping the new one is okay.