Engine shakes and low power

Hello, it sounds like the Catalytic Converter is plugged up. If its glowing red, it melted down inside. This happens with an engine misfiring and raw fuel is going down into the converter and overheating it. There could be multiple reasons cylinder #2 isn't firing. It could have a bad injector driver from the ECM. Do you have spark at cylinder 2?
You can put compressed air into the cylinder and see where the air is coming out, i.e. intake manifold, exhaust.
You just have to get that cylinder up to top dead center on its compression stroke. You can do this by putting a compression gauge in that cylinder and turn it over by hand until you see the gauge move up, get that piston up all the way and most compression gauge sets can hook an airline up to. This is pretty much a cylinder leakage test without the leakage tester gauge.

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

https://www.2carpros.com/articles/how-to-test-an-ignition-system

If you're sure you had the cylinder at top dead center, if it's not exactly at top dead center on its compression stroke a valve can still be open just a little. So, you have to be sure the piston was up all the way. Unfortunately, because you had a converter that was glowing red, it melted down because of too much fuel going down the exhaust. If you did the cylinder leakage test correctly, there is a burnt valve. Valves can burn when there's too much carbon build up in an engine, and what happens is the carbon is so hot that the air/fuel mixture ignites before the valves close. This causes pre-detonation. And burns valves. To replace valves the head has to come off, it should be sent out to a machine shop to be resurfaced, in case there's any warpage on the cylinder head, and they can replace the valves, the valve seats and guides, springs etc. Since you've replaced pretty much all the ignition parts and fuel injector. But unfortunately, the converter is probably no good either. You may want to unbolt it and take a look inside, I'm sure it has melted down.

But really make sure you had the piston on its compression stroke and the valves were completely closed during your leakage test, before you pull the head. You don't want to pull the head just to find there's not a valve problem and it just wasn't seated fully and the piston wasn't all the way up. If you get what i'm saying, I just want to make sure you did the test right is all.

Was the car smoking a lot? White smoke pouring out the exhaust?
I have had cars where the fuel injector driver had failed in the ECM, and it was keeping the injector open all the time, just pouring fuel down into the cylinder. Pouring white smoke out.

Hello again, so you did have a compression issue, do you have a scan tool that you can look at live data? And are you getting any codes? Running rich at idle sounds like a vacuum leak. Vacuum leaks will improve as the throttle plates open, so under high speeds, higher RPMs, more throttle opening. The reason a vacuum leak will be worse at idle is because manifold vacuum is at its highest with the throttle plates fully closed. So false air is getting in somewhere else besides the air intake tube. But if you had a scan tool to watch live data like the oxygen sensor activity, fuel trims, etc, we could tell more of what's going on. If it's affecting all cylinders, it can be an air leak, skewed oxygen sensor, MAP or mass air flow sensor, etc.