Hm, it seems you need to revert the change from post #40 then:
sudo sed 's/fb1/fb0' -i /usr/share/X11/xorg.conf.d/99-fbturbo.conf
This is weird, as per this thread I would have expected that your screen uses fb1 and not fb0… Sorry for asking, but want to make sure: Is your screen an original Waveshare 35b and also V2? And is it the only screen connected to your Pi?