Hello!

Among the rocks of my bonsai where some moss used to be (put it there but it died and i removed it) there's some strange white dots that look a little on the fluffy white mould side of things. Is this normal and okay to keep there, or do I remove all "infected" rocks and soil?

Thanks!

could be mould, could be scale.

I generally do not worry too much about these things. PLants in pots are virtual ecosystems in themselves with lots of things making a living. Only a fraction causes trouble. If you rplant is healthy and growing normally nothing to worry about.