Well, maybe but why does it stop leaking after a few days and also if it was a leak it probably would not fill up the carbs and then run down the foot. I don't know.sounds like you have a leak somewhere, you could eliminate the oil pump, and go premixed gas.
Another question. Can I use a Minn Kota Maximizer with a Motor Guide trolling motor?
Minnkota's maximizer is a technology integral with the motor and controls. There is no convenient way to integrate that system with a Motorguide motor. The advice you are getting for your oil injection is a little suspect. the oil tank must be vented or oil would not flow out of it during normal operation. Since it's vented, pressure cannot build up in it. It would appear there is residual pressure in the injection pump after shutdown which forces oil into the carb.