> DO NOT MENTION, OR INSINUATE, YOU WERE FIRED. And don't lie.
It's unfortunate that openness is punished so harshly, but I get it. You're not the first person to caution strongly against letting anyone learn about the termination, so I'll try to move forward accordingly :)
> I try to avoid saying negative stuff about my last job
Definitely agree. It's one of those things that's more likely to harm than to help.
> herniated disc / sciatica
my sincere sympathies. I herniated some (cervical) discs a few years back, it's an extremely frustrating condition. In my case it's gotten better with time to the point I can do almost everything I could before, but I don't see myself getting back into MMA or other full contact sports.