The first pic is from the front. I know the crack isn't good but it's been that way for awhile. I'm more concerned about the following pics through the O2 bung. Does that look normal?

 

Lol
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Yes. You had to ask??

 

Cats are typically docile creatures, but can on occasion get into trouble.

However, the catalytic converter in these photos appears to be breaking apart and probably should be replaced asap, but apparently you knew that already and have been ignoring it despite the potential outcome. That’s how we humans occasionally get into rotary engine replacement trouble. I never realized that was the kind of thunder you were trying to make.

 

So what are my options if I want to keep it emissions compliant? A new oem S2 cat is $2k+. The car is probably only worth $10k if I'm lucky

 

Catalyst is cooked --- you can punch it out with a metal pipe to assure no risk to the engine, at least until you find a new catted midpipe or a shop to weld-in a new cat. You'll want a high-qualtiy metallic catalyst as the ceramic ones don't tolerate the exhaust heat of these engines very well.

 

I can't really tell but looks like your secondary substrate collapsed which causes potential blockage. Not good for engine.
You can always visit the local salvage yard to see if there are any rx8 with cat to purchase.