Dodge - Charter :: 2007 - Code P0158 / Bad O2 Sensor

I have a 2007 Dodge Charter 3.5L v6 Automatic that is having a few issues that I think are related. It all started with a P0158 Code O2 Sensor Circuit High Voltage Bank 2 Sensor 2. Had this go on my previous vehicle so I inspected the O2 Sensor on passenger side closest to the back of the car. Wiring harness is fine, so I replaced the sensor. The code came back after about 3 days of driving (30-60mi/day).

Then I remembered some of the other issues I thought were not important, but wondering if together they mean something.

1.) While idling the engine seems to stutter, almost like its about to stall. Almost like it is starved of fuel for a second. This happens maybe 3 times a week.

2.) One out of Twenty starts are rough. I will turn they key, the starter/engine will crank and will take about 3-5 seconds to turn over.

3.) Significant drop in gas mileage. I usually get 340-350 miles before my low fuel warning light will go off. Now it will go off at around 290-300.

4.) When filling up at the gas station, the pump will shut off like it is full, when I know for a fact it is not (i.e. putting 1 gallon in when the tank is half full). I have tested this with the tank at multiple different levels and the issue always occurs. So even when my gas gauge tells me I am full, I never really know because the pump shuts off multiple times. That could be the reason for the mileage short, my tank is not actually full (fingers crossed).

5.) My OBD2 reader is showing the following information other than the code above: Readiness Monitors - 5 Complete, 3 Incomplete. The monitors that are incomplete are: Catalyst monitoring, Oxygen sensor and ERG system monitoring.

So my questions are: Did I replace the wrong O2 Sensor and is the Bank 2/Sensor 2 on the left (drivers side) and not the right? Is the issue the Catalytic Converter (I would assume the car would be throwing more codes at me)? And lastly, am I the lucky guy that has the last, and most unlikely, issue with the P0158 code and I have an issue with my fuel pressure/delivery system since I am getting gas fume kickback causing the gas pump to shut off prematurely?