It dismissed little bits of the episodes in order to keep the flow, but they added a heap more Sammi development to balance it out. I don't remember Akiko talking to Rikou that much neither.
From memery, he just sat down and played the piano after Sammi did without expressing his thoughts like he did in the movie.
It's the best bet. There's no other person it could be. They gave a much better explanation of what the reading-guy in the suit was doing, but exactly what his organisation was doing is still going over my head.Was the old man with Nagi during and after the credits Shiotsuki?
A sequel would be nice - they could even do it in little episodic instalments again.