Player movement between NHL/AHL remains the same, I think, as does the edit lines screen.
Prospects from the USA, Russia, and other nations will be generated for each year. I think it was in a recent blog that they used actual draft data to better match the quantity & quality of generated prospects to real life trends.
As for the AHL age rule, I didn't think to check that at the community event, nor have I remembered to do so with the retail version. Guess I now have something to do tonight, eh?