I can't speak for the quality of singing, but it was pleasant. Did the others (playing that part) sing also, or was it omitted? The language barrier really does make vetting the 'acting' quality parts more difficult for me, not that I'm an expert otherwise.

I also half expected a 2-in-1 flashback of Sawa's major malfunction.

Does Sarasa actually know about his (father's) meddling? I didn't expect her to intuit that much.