Art-directed watercolor stylization of 3D animations in real-time

Could it be implemented in blender?

Could be implemented? probably, yes
Will be implemented? Probably, no

But you can talk with dalai or clement, maybe they like the system for eevee NPR

Example: https://www.reddit.com/r/Art/comments/6j1lod/bat_in_a_coat_digital_3d_540x540/?st=j7okc3w8&sh=030ff30f
Process breakdown: https://imgur.com/a/giK3y
Not done entirely via Blender, but don’t see why it couldn’t be.

Who are these artists who are all using same paper awful for water painting ?

I have subscribed to the forum for this at https://artineering.io/research/MNPR/ and conversed with one of the authors. This project is directed towards Maya users, but it has Open Source archives and a lot of Python code. I asked him about a Blender porting, but license issues and wanting to maintain proprietary hold on product sales, make this unlikely. I suggested Lightwave as another choice to be able to sell Plugins, and he confirmed his own history of using Lightwave but did not have any plans.
This approach would be welcome in the Blender community, for animation and illustration work, reminds me of some of Sylvan Chomet’s animation work, in a good way.
I am utterly incapable to understanding the Python implementation, but thought to bring it up to work with Freestyle, the new NPR development in the 2019 Summer of Code, and Eevee or Cycles.
Just some questions to the NPR community and developers everywhere.