Leave the stone fireplace alone. Lighter walls will go a long way to brightening the room.

Don’t paint the stone. Maybe change the mortar color to a lighter color? And I’m not sure if all that tile in front of the fireplace is necessary. A single flooring would look better. And wood paneling belongs in the 1970’s. If you can not remove the paneling there are ways to successfully paint them. Do your research don’t just brush paint over the panels.