P0420 - Exhaust Leak

My 02 3.4 is throwing a p0420 code. I performed a smoke test and found two leaks. One at the flange after the rear cat, but before the rear o2 sensor, and a second coming from behind one of these shields/guards that are located before the rear cat.

Any idea what these shields do? Can they be removed so that I can fix the leak behind them?

 

https://www.tacomaworld.com/threads/addressing-some-common-misnomers-of-the-p0420-code.396763/

Some guys on page 2 or 3 found the same thing and remedied by replacing gaskets and slapping RTV around the flanges.

 

Those look like heat shields. What's around them--any electrical or soft parts? It looks like they'd be easy enough to grind off and put back if needed.

For whatever it works, I just replaced all the gaskets in my exhaust to remedy a P0420 (code-free for a week now, so it seems to have worked) and I don't recall seeing any shields like that.

 

I believe there’s a shield for the rear O2 sensor.

 

I don’t think those heat shield should be welded to the exhaust like that. Maybe I’m wrong. I wouldn’t worry about the heat shields. Remove them and fix the leak. I had a P0420 code caused by a similar leak between the rear cat and rear o2 sensor. Fixed the leak and the code went away.