First of all, just how high was the level?? Overfilling is not going to raise pressures and cause the pump seal to “Blow” out. The pump could be “venting” It is quite common for a pan gasket to leak after the pan has been removed. Pans need to be perfectly straight when reinstalled. Prying the pan off during service will cause it to leak if not careful so I can see it leaking after the service. If replacing the pan gasket again cured that leak then I would first just clean up the trans and get the fluid to the proper level. If the pump was just venting then the leak should stop from the bellhousing area. Watch it carefully for a couple of weeks because you might still have some residual oil in the bellhousing area that will drip for a short time. If you notice the trans still leaking from the bellhousing area then the trans probably did have 2 leaks and it would be time to remove the trans and replace the front seal and bushing. Let us know how it comes out.
transman