2002 Ford Escape oxygen sensors/ catalytic converter?

I had a mobile mechanic come out because the check engine light came on. He changed out the valve cover gaskets and did a tune up with new plugs/wires/air filter. Started the car and it ran really rough. We rented a diagnostic tester from autozone. It read that it could be the o2 sensors. Codes were p0443, p0161, p0155, p0141, p0135. Well the catalytic converter under the car got bright red with the heat it produced. So the mobile mech replaced an o2 sensor right by the catalytic converter. Car still ran rough. So then I drove it over to a shop and the mech there kept it a week. Ran a diagnostic and replaced a bad o2 fuse. The check engine light turned off and so far hasnt come back on. But the car still ran really rough. Mechanic said he couldnt figure out what was wrong. We drove the car home. I topped out at about 15 mph as the car ran very rough. Was about 2 miles from my house when I couldnt go any further. Car had no power. I looked underneath and the catalytic converter was so hot it melted the plastic shield in front of it. Weve spent about 400 bucks on mechanics who cant find out whats wrong. Could it be the catalytic that keeps the car from running right and having no power and showing bad o2 sensors on the diagnostic? Any ideas please. Thanks

Don