I am currently stuck with the same problems. Don't have a solution yet, but a little help:
Next up, I can't use the volume adjuster keys without the volume slider going crazy and locking up my menu options and pretty much everything else making my system unuseable until I reboot.
The Fn-keys don't work properly (a nuisance to be sure), so I try to avoid them for the time being (i.e. until a fix has appeared). If I hit the Fn + mute button my keyboard is mostly lost (e.g. can't type text anymore). To avoid rebootig the system too often I just switch to a regular console (with [Ctrl] + [Alt] + [F1]) and then return to X (the graphical interface) with [Alt] + [F7]. Now the keyboard works again. The same should be possible for the volume-Fn-keys.