The current wall color is much more up to date than a grey; grey walls would immediately date the house - and not in a good way. Also, the current wall color works much better with the style of the house, than a grey would.
So I would leave the current wall color, as is. I‘d also leave the stone fireplace, alone.
If using vinyl plank, I would run the same vinyl plank flooring throughout. And call it a day.
Q