That’s very possible, tho then we may end up back to some of the reasons (guess work) as to why the movie got cancelled. In that doing something like the above maybe didn’t fit with the directors vision or to make it all work together would require more development time in areas that at this stage may not even have a clear plan/design worked out.
Yes, my understanding is a lot of that was ‘experimental’ and a total nightmare that would fall apart/crash if you just looked at it the wrong way. As such, much of it never made it to a final stable release of Blender.
Yes, based on theses tests: Cloth Simulation- But With Nodes? - #5 by Xeofrios it seems the first thing we may need is sub-stepping in the sim nodes.
Cloth I’m not so sure about, but fluid, yes, since we already have a very viable solution in Flip Fluids. Not really any sort of equivalent addon for Cloth or Hair at this stage.
That would be nice, for hair and cloth, pretty sure such a library doesn’t exist at this stage.