I'm probably going to go for a mix of 2D and 3D as I think it will allow for a much more interesting look and could even speed up the production.
Another thing that keeps demanding my attention is the idea of adding about a minute of back story to the movie to further establish the characters and add some anticipation for the song. I have done some rough thumbnails to storyboard this addition but am not completely happy with it yet.
I have worked out that there will be at least 18 characters that I will have to model, texture and rig for this, even though most of them will only be seen for a few seconds. Lots to get on with and I hope to start some of them this week.