[Tcoat]

Your battery was below the required voltage/amperage to start the car. Yes, the lights and other accessories work because they simply do not need the same amount of power as the starter. The boost cables were probably bad so that is why it didn't charge up with the boost but did with the charger.
In your attempts to start the car you dropped the battery power below where it need to be to keep the different computer systems working and that is why the car reset everything once it did get enough again.
The CEL could be related to the drop in power or could be something totally different. There is no reason to assume it is from the O2 sensor. Need to take it to somebody that can read and clear the code since any other speculation is just wild guesses without any data.