It all depends on HOW it goes bad. If it blocks the outflow of exhaust gas, then the distance you can drive before it begins to decrease power will become shorter and shorter until you will have trouble getting out of your driveway.
If it blows through, then you can drive indefinitely (or until the next state inspection).
Yes it does.
Yes, you can do serious damage to the engine if the converter is clogged.
no it will run rough and stall out
There's no possible way to pass inspection with a bad catalytic converter, if if you find out you have a bad catalytic converter during your inspection you have a chance after you after you have replaced the catalytic converter and the inspection no no charge/free!!
A catalytic converter should NEVER go bad unless something causes it such as a RICH or a LEAN condition. What is a "RICH OR A LEAN CONDITION"?
Don't let your car idle for long periods of time.
No. A catalytic converter wont. If its a rear wheel drive, check your drive shaft. Front Wheel drive, CV Joints. Other than that worn steering. Exhaust wont cause this issue.
Safe, yes, smart, no. Damage can occur to the Catalytic Converter.
No, the catalytic converter is downstream from the EGR valve so it has no effect on it.
Transmission torque converter or an exhuast catalytic converter?
Technically, quite a while. You'll just find that your mileage goes down the drain. It will also eventually destroy the catalytic converter.
A bad coil can damage a converter. If the engine is misfiring, it will cause raw fuel to get into the converter and that can cause failure.