well my first attempt at unlocking, decrypting, installing TWRP went well, unfortunately ended up with a lot of ggogle services force closures and that annoying meesage on boot that my system cannot be verified please lock.
Tried installing n6pangler rom from XDA but somehow the radio did not work. I think the simple days of flashing just the rom maybe the gaps is over. Now you have to flash or fastboot flash radios, boot img ect each time you want to change roms.
Decided to go back to stock and relock my phone using this guide
http://forum.xda-developers.com/nexus-6p/general/guides-how-to-guides-beginners-t3206928
at least I am on the latest build MDB08M from
https://developers.google.com/android/nexus/images?hl=en
I think waiting a few month or two until a worthy rom comes up and everything is hashed out is prudent.
Native wifi hotspot works anyway on the stock rom (on verizon unlimited) which was my primary concern.
Wanted root to use Titanium back up and restore my save games
Helium sort of works not transfer some off the save files.
good luck and happy tinkering