I like the ideas with Maul and Vader beng shown after the medal ceremony. However, I would not add any character names in the dialogue cards unless you plan to do it with every single card. The people that complain that they don't know who is speaking just don't know the movies well enough and should probably watch the originals a few more times. ;) If you start adding things like that, especially just to a few cards here and there, it's going to start feeling like you're holding people's hands to help them "get it." I think it's a bad idea. If you look at old silent films, they never had to resort to this. Don't get pushed into doing something that might look odd just because a few people don't "get it." ;)

Your first idea of "edit minor shots of speaking characters for a clearer understanding about who talk, and to whom" is all that is needed. And I don't think it's needed at all! To be quite honest, I barely know the PT compared to the OT and I never had a problem understanding who was talking to who.