okay, did you allready know a program called Kextupdater?
Please have a Look at the download section/ tools and Download and install it. Afterwards you should update all availabe Kexts to see in there are positive changes.
Following this thread it was the solution to fix the trackpad problem. We couldn‘t find a solution for the Audio at the time, but maybe ist solved with the new Kext also?
As I didn‘t own this model anymore it will become difficult to support for me, but I will try as far as I can.