Regarding the lack of songs in act two, here's where I imagined Sondheim wanted to fold them in:
- The Water Hysteria Scene
- "Being"
- Resetting everyone back to Square One
- Finale
As mentioned before, the lack of a finale song –really the lack of any music at the very end– was the most disappointing. Surely they could have simply repeated an existing song –perhaps having everyone recite a piece of something earlier, or turning the Buy This Day solo into a group song (no modification to the music besides adding in other singing voices), or simply repeating something.
I also think that given the content of act two and the style of music, I wouldn't mind at all if Adam Guettel contributed 4 songs to round out the show.