The cat isn't going to just plug up instantly with the amount of oil you put through it. And, . .given the cat was cold it would have let the oil go right through rather than reacting and burning it. I would not got here just yet.

Is the MAF wire plugged in?

Is the air tube from the MAF to throttle installed so there are no leaks?

Any chance the EGR vacuum hose was swapped for the AIR vacuum hose ( AIR pump ). Both valves are in a similar location center of head above the exhaust manifold on the 94.