Don't dump your intake manifold upside down over the open engine. I lift straight up and get it away from teh engine.
After you've drained the radiator, and you pull the alternator and it's bracket..there is very little left in the manifold. Keep it reasonable and you won't be filling your motor.
Doing an LIM job, I don't pour oil through unless I have one dump coolant (happened once, and only once). Then I fire up the car to ensure it's running well, turn it back off and change the oil, keep filling coolant etc. Then run it to top off the coolant and look at the oil. If the oil gets milky.. go buy two more oil changes. Like I mentioned though...ONCE
The info about the oil pan is to remind everyone that water will sink in the pan and sit in the bottom. Pulling the plug won't help. You won't be able to get the last 2 cups out of the bottom of the oil pan w/o running the motor and getting the fluid mixed up. So if when you do your first oil change, if you don't see any milkiness, then you are ok.