Hi @alpinist,
since in go back and forth in every image i had to look what i did in the end 
I think i only apply the lens correction module by default. I use the other modules for each image according to mood I want to achieve.
With the highlight reconstruction I test which mode looks best on the image I currently work on. But I discovered that the “reconstruct color” is very good on reconstructing clouds on most images.
The Demosaic “two times” is a preset added to the module. ( I didn’t put much thought in this 
)
Yes you are right the “adjust autoset parameters” is not necessary. When i exported the image the first time i had heavy noise on the image because i used two “Contrast equalizers” and no denoise which sharpened the noise heavily and in played around with the parameter. But for the end result it is not necessary 
They use the same mask but different gray values for the parameter masks. So that the first only affects the brighter areas and the second only the darker areas. Then i darkened the dark and brighten the bright areas to get more contrast on the mountain. I’m not sure if this is the recommended method because I feel like this should be achievable with the local contrast module?
The “local contrast 1” uses the blend mode: multiply reverse that I picked up on this thread Clarity in darktable
I hope this clarifies some of you questions