The dissassembly of the keyboard is more difficult than I thought and I broke some hooks with this guide. The keyboard is hold in place at the bottom side while there are very small bend hooks at the upper (screen) side that keep the keyboard attached to the frame below. I ended up just bending these hooks to get them out of the frame and in again.
I had a problem that is so common that I would love to see it as a comment within the guide: I spend the better part of a long afternoon reassembling different top cases and cables with the result that trackpad and keyboard didn´t work but the power button did. Sometimes both were working for a few minutes and next time I would start up they would be dead again. Solution was: The small cable that fits into the trackpad / USB Controller and takes the trackpad / keyboard signal to the logic board has a widely documented tendency to loose touch with its connectors after a few years. What helps is to apply pressure on the end of the cable where it enters the controller below the trackpad. Easy to check with fingers. In the long run use a piece of a thick plastic card or cardboard to apply pressure from the battery direkt on that spot. Easy. And works like charm. After I was so close before giving up my Macbook Pro or buying another topcase. Please add that possibility to the guide as it is really common.