I agree with CCS. Plus, Qui-Gon is supposed to have discovered a long-lost technique to use the Force this way. I'd say the technique is to keep consciousness and not a technique of "being summonable to give a piece of advice". It's not the technique used by Sheldon to speak with Professor Proton.
Spoil of RoS:
In RoS, I am pretty sure I recognized Mace Windu's voice among the Jedi who speak with Rey. She has never met him and, while we can see Luke and Leia speaking of Yoda and Obiwan to her, it would be strange that she would think of summoning the voice of Mace Windu for advice. And other voice I didn't identify, so I would think nobody cared enough to tell Rey about them... They must have chosen to speak at this time, using the technique "Manifest outside of the Netherworld of the Force". I imagine a gigantic, empty lobby with thousands Jedi Master standing around, until Qui-Gon arrived saying "hey, I've found a way out!"