I agree with Eddie! You probably should wait about explaining how the saber got to Maz until we see if Episode IX says anything about it.

As far as when Rey could hear voices, I think they aren’t really necessary for TLJ.

While I understand why you have that idea, I think hearing faint laughter when Rey lifts rocks could take away from the drama of the moment.

I think little things like Rey hearing voices before she sees the Force tree, and Yoda showing up later in the movie could help connect the Force guidance idea. Maybe at the most you could add Yoda, Obi or even Qui-Gon to the voices she hears in that moment.

But as far as TFA, these are the moments I think it would be appropriate for her to hear voice echoes:
In Maz’s castle, calling her to the saber.
During the Force vision.
If you give her a dream before she wakes up in the interrogation room.
Maybe during Rey/Kylo’s mental fight.
Maybe during the mind trick scene.
When Rey and Kylo have their saber’s crossed.

I think that would be a good amount, give or take one or two, without it being too much.

Also, I see that you you’re gonna cut Luke’s island stuff from the end of the movie and make some of it a dream earlier in the movie. I think I’d like to see it, but I think you lose something by not having Rey ascend the “Jedi steps” and finally reach Luke at the end of the film. Would you bring all of that stuff into TLJ? Just don’t know if it would work. Also would hate to lose that cool “Rey’s journey” idea you had for it.