Low coolant can be air trapped in the system, the sensor gets a air bubble trapped around it usually, that's common. You might also check the reservoir and make sure its filled up to the HOT mark, and make sure your radiator is topped off too, since I think you only added coolant to the radiator only.
oil pressure problem, not sure. The pump is pretty much fail proof. I have never seen one fail before. I have seen the pumps grind the crap out of a front cover before...but never fail. Low pressure can be cause by a number of things if it is indeed low pressure, and not just a dummy light misguiding you.
Your engine oil should always be at the full mark, when we checked yours after you started it for a while, yours was reading about 1 to 1.5 quarts OVER full. I checked the dip stick three times, same reading each time.
If you JUST filled your oil and have not started your car, it will read a little high (not 1 to 1.5 quarts high) sure because its all in the pan, and nothing has been pumped up to the top end, or the filter hasn't been filled completely.
~F~