I would not paint any stone or brick that isn’t already painted. Your rock wall looks great to me, but I think the ceiling paint color could be a better match to the stone… a cream that’s less yellow maybe?

I would probably paint the light green walls and cupboards in the same mushroomy color as the wall near the stairs. I would also repaint the brick in the bathroom, but not sure what color…. :)

As mentioned by party music50, the stone is very nice, I wouldn't paint it nor the brick if not already painted. To make the room brighter, I would paint the ceiling in the entire basement in a warm white. I would paint the entire area at the bottom of the stairs in a creamy white, and if the brick in bathroom has already been painted, I would paint it in the same colour as other walls.

This is gorgeous!! Thank you!