Yes
Yes
Yes
The engine should be hot and idling in park.
Dodge Avenger has a problem with this. You need to take off the oil pan because the oil thicken's in the pan. Clean it and put it back on and this should to the trick.
Engine idling in park
Enough to get the level to the safe zone on the dipstick while idling in park. It depends on why you are adding. If you changed the filter in the pan, start with 4 quarts.
The same on a car equipped with manual transmission. On an automatic equipped car it will use less idling.
Idling in neutral.
Trans fluid is always checked with car level and idling while warmed up.
Well, a transmission itself does not idle...the engine does. A vacuum leak in the engine will cause faster idling or slower idling depending on where the leak is. Newer transmissions do not use vacuum at all for their operation. Older vehicles used vacuum to help with the shifting of gears-automatic transmissions.
Transmission mounts are bad
Yes, idling in park.
Leave idling, on level ground, at running temp
Engine idling in park.