It looks like you have a fairly large project and a very interesting house with a lot of potential. It is very difficult to give advice without knowing what it is that you are trying to do....

From the two photos that you posted I can only give a bit of advice based on what I see...

The kitchen marble (or granite) is a bit overwhelming. I would consider replacing the backsplash with a simpler and less busy material. I would probably paint the island a different color than the rest of the cabinets to add some contrast to the space. Perhaps a soft green or grey....

The living room is dated and needs updating. I would modify the light soffits on the ceiling and add new and different lighting and ceiling fans.

I would remove the large marble bar ( or whatever it is ) on the right of the photo.
The fireplace needs updating

The flooring looks interesting and will probably look really good with some big area rugs to soften it up ...

My biggest piece of advice is to look up on houzz, "find a pro" and hire a good architect and / or interior designer to help you with the changes............good luck.

Thanks. How would you update the fireplace? Replace the flagstone with stacked stone or tile or ?