A: The input you can use for simulating sound transmission in Odeon is the sound reduction Index for a certain type of wall.
Odeon does not take into account flanking transmission.
You can use Odeon for simulating sound pressure level in the receiving room from a well defined source, if the flanking transmission does not play the most important role in your construction, compared to e.g. the room acoustic complexity of the rooms. If you know the influence of the flanking transmission you can manually include it in the sound reduction Index for the wall.
It is important to check the reflection density in the receiver room. (You do that from a point response / reflection density). It should be more than 50 if you want good results. If it is less you should increase the number of rays.
To make simulations according to measurement standard, remember to use the required amount of sources and receivers.
Video describing how to simulate sound transmission.