Now this is still a very long way off but it's something worth thinking about.
Was messaging fellow classmate Clym Smith today and he had two very useful videos which show a great way that 2D and 3D have been mixed in the past. The first is from an animation called 'Burning Safari' and (quoting Clym here) "is a mixture of 2D matte painting backgrounds with 3D elements (mainly foreground rocks/trees and characters+spaceship)"
The next one, 'Pyrats', "is a mixture of 3D enviroment (buildings, camera movements) with 2D animated characters."
(Just like to note that on the original animations the embedding was disabled so those are links to the 'making-of' but if you go to their youtube pages there should be a link to the actual films at the top of the list on the right of them.)
Both of these animations have been pulled off very well and the 2D and 3D run seamlessly and make the different media work. Personally, I like the way the second animation has been created, mainly because I'm a 2D person and I adore 2D animation, but for this project, with my level of experience I think the first animation style would work better. In the end it all depends on how the rest of my group feel and whether they want to include any 2D at all (which I really hope they will!). Either way I think I would be happy with the result as they look amazing.
Now I must get back to storyboarding...