Yes. No need to flash the secondary twrp.zip on the 6p. That's only for the P2XL
So I don't mind using fastboot.. feel fairly confident about the process..
My only concern left is can I use the downloads that mention "Softbank" ?
Seemed like I saw somewhere that has something to do with a Jap or Kor source or for those devices or something..
All the downloads are here: https://developers.google.com/android/images#angler
Can I use "8.1.0 (OPM5.171019.017, Mar 2018, Softbank)"
On a US N6P ?