Digital Light & Color

I'm trying to grasp what adjustments, mostly in colour balance, make e.g. Fuji film simulations so distinctly recognizable (and to me pleasant)?

Not that long ago it was fairly easy to tell what slide film was used just by looking at the picture. The simulations are less distinct, I think, but still visually unique.

What I struggled with was not as much the desire to slavishly replicate the Fuji film looks - although that would also be nice - but proving to myself that I understand the image processing enough to be able to do that. I'm not sure if I do.

When using the reference values extracted from JPG produced similar output to using the the reference values that came with the target, where those two corrected RAW output images also similar in appearance to the actual off-camera JPG?

I'm pretty sure what they are doing is creating different camera profiles for each film effect, but in order to apply the profile and get consistent results, they are probably doing other things to normalize the image, such as adjusting the brightness, contrast and color balance. If you really want to experiment with this and have a calibration test target -- preferably one with more patches than the 24-path ColorChecker, I can uncomment the feature I added to Create Profile so you can create new reference files based on the JPEG image of the test target.