I just found a solution to our common problem, hope it works for you as well. Apparently not only FP related. I followed the guideline here: https://productforums.google.com/forum/#!topic/nexus/DRVyGHFAdjA (it’s about Nexus), which worked fine. Got my tethering back, both WiFi and USB (haven’t checked Blutooth). You might want to use “Minimal ADB” from XDA developers instead of downloading the entire SDK as suggested in the original post. “Minimal ADB” worked fine for me.
So, 2 of my 3 major FP2 problems solved today - now I lack a solution to my Blutooth problems, but that’ll have to wait for another day.
Good luck!