Colour grading is indeed a skill but no more time consuming than any other part of the editing process, once you get use to doing it, like any other part of the process...
The Fuji jpeg engine can introduce grain into the images, more so in Acros and you also have a grain option setting in camera. Saying 'his images are always extremely clean from his bodies', are you implying that Fuji files are not clean? Having shot with both systems I'd differ in my opinion based on experience there. Fuji files are plenty clean if you want them to be.
Yea, Kevin says he shoots a little underexposed and uses spot metering a lot, so that will give a lot of dark areas. He also set his shadows to +2 and highlights to -1 so you can guess his style there, Works for him.
Lightroom is a raw converter and a good way of cataloging images, raw conversion is what it does. I tell you loading 2000 raw files into lightroom will take a whole lot longer then importing 2000 jpegs. As the raw files are a little over twice the size of the jpeg [In colour, less in B&W]. Outputting files is the same speed so if you are processing them the time is already spent.
'Back in the day' we would process colour film to B&W, it was called 'cross processing' & printing from colour film to B&W was also done, Google Kodak Panalure paper. Nothing has really changed just gotten more instant.