The Tuneful Tuna

I've been toying with the idea of turning my novel into a literal (a literary musical without music; aren't I funny :o) for ages now. The idea first occurred when I was playing with the revelation scene where God tells Corus the time of his death. How might this happen? thought I; do I want this to be deadly serious or humorous or what?
Given that I deal with an awful lot of disturbing concepts throughout the novel, I figured it'd be fun to have the fish man drive up in his van and Corus looking at the fish in their trays of ice, and then having the fish sing, creating solos (for the lemon sole perhaps) and harmonies and so on in the form of a libretto (which would tie in with Corus' love of opera and with his God-ordained task of transcribing a composition that has been implanted into his head).
I ran this idea by a few of my beta readers, along with the first pass of the song, and the overwhelming response was very positive.
Then it occurred to me that I might be onto something, and have since looked through the ms for moments that I figure could do with a little levity. And now I have lots of songs ready for insertion at appropriate places. Now I'm curious about how these will be interpreted; I'm really only creating little more than poetry, or lyrics - although I can hear the music in my head too, but it tends to change from one day to the next. However, using rhythm - the beat of the words - I can convey some music forms relatively easily, such as a march or a waltz.
This is going to be one of my first tasks once the ss competition closes (end of Feb) and I return to my ms. I need a greater spread of emotions and I need to deformalize Corus' narrative. I feel that I'm about ready to head into the ms again, and that all will be well for a short time longer!