Low vacuum cracked ceramic in Catalytic converter

`989 XJ6 XJ50 3.6 apprx 130K miles VIN last 8 is 576021
Bought in 2004 always ran well though there was a hairline crack and minor leak on rear exhaust manifold in 2004. Recently the car has lost power and the crack had gotten larger and some EX MAN nuts were loose. Removed both manifolds though the CAT below not dropping made it difficult. They are out. I checked compression reading of all 6 cylinders and are within 10 PSI
CAT looking inside on tube it is all crumbled…

1 Replace CAT and or replace with bypass pipe as pollution inspections are not done for old cars. A part number and source for a bypass or new Stainless cat??

2 Why did the exhaust pipe not drop. it made it challenging to wrestle particularly the rear EX MAN out

3 Yes lately the idle vacuum has been very low and car had no power mostly due to bad CAT CONV and loose exhaust manifold bolts??

4 CAT with exhaust manifolds removed will it come out the top of engine??

Car is in a tight garage no access on passenger side limited access on driver, may have to roll it out so as to remove the CAT and get it all back together, have new exhaust rings and exhaust gaskets.

Thanks to all…