I have a 2007 Lexus GS 350 RWD and I am getting the code to replace my O2 sensor (bank 2 sensor 2)

I have read over a couple of threads here and thought it might be a project that my significant other and myself could perform.

Having two major issues:
1) The O2 sensor that is exposed under the car is seized up or corroded and I am unable to get it unscrewed. (WD-40 it and turned on the vehicle to warm up the pipes but still a no go)
2) I cannot locate the plug inside the cabin to disconnect it. (I read several places that you can forgo removing the drivers seat and just push it all the way forward and remove the vent panel to access it, but I’m not sure where it’s supposed to be. There is no way to look in the and I’m just maneuvering my hand around trying to feel the cable.)

My questions...
Does anyone know if the O2 sensor or the threading would be damaged if I connected the Crowfoot Wrench to an Impact drill?
Right now, I am going to let it sit overnight with tons of lubricant to see if it helps loosen it up.

Does anyone know what direction I should be feeling around for the plug for the O2 sensor plug?
If all else fails, I’m going to remove the Driver’s seat to find the plug...
Does anyone have a manual or directions on how to remove the Driver’s seat?

Thanks in advance for your helpful responses.
^.^