Like I stated earlier - you have circuit failure codes, fluid and temperature has nothing to do with these codes.
Look the harness over real good for chaffing or damage. From the controller down to the trans.
Carefully pull the connectors loose and clean and inspect for corrosion, both the female and male ends.
Switched battery failure stands out like a sore thumb.
It's dragging because you are in default third gear. If you can pull it in to low and it accelerates like it normally would that confirms default/third gear start.
Converter has nothing to do with your problems at this point.
And yes the O2 circuit can wreak havoc on trans controls due to the sharing of the harness at the splice.