I would imagine that VDP is providing the structure (conceptual storyline) and if Brian is happy composing a whole pile of bits and pieces to hang on that structure.. then great!
From what I've read and other sources, I doubt very much if this is what's happening. Was VDP mentioned from the get-go ? Nope. My impression is Van Dyke providing lyrics to existing music.
not surprising.... BW has been recycling his musical fragments since the beginning....
still feel upbeat about the whole project....