Out of this project, why not create a good tutorial on to achieve it and how, perhaps, to improve it ? It might be a good idea and it'll give you a break so you can continue on your other projects.

About the "grain" & flatening image story, I think that, based on people's opinion, maybe this project (and probably others) could be revisited to correct those two problems, especially the loss focal lenght with the background.

In my own opinion, for acuracy's sake, unless proven otherwise, I think all Disney modern animations post Toy Story were all transfered to film for their initial release. So the "grain nostalgia story" in Disney animations shouldn't go any further than that. So, should the grain in BATB be back as an important element ? Yes I think so, especially if the reved grain flatened the image to the point of losing focal lenght with the background.