That's the problem with the internet because there is always air getting around things fluid won't near as easily.
Hearing air leak is normal (to a point) and it all comes from the center front of the trans under the drums.
For the drums it leaks air around the pump stator, and the same for the kickdown band but not as much.
The rear servo is usually real quiet since it's a rubber seal.
Are you hearing a THUNK when you apply air to the drums?
If so it's probably ok.