Remove the mirro it reflects nothing worth seeing twice . I do not like all the stuff on shelves in kitchens but if this is the look you love then get piece of art thay would look great in the kitchendecor and put it on the mantel to beging with then candles more like the ones in the kitchen only a bit taller and bigger around . IMO the Edison bulbs in all the fitures are casting a yellow glow on everything IMO not falttering but you need to decide if that yellow glow is what is making your kitchen feel warm along with the kitchen wall color, which I bet if you changed all your bulbs to LED 4000K ,would look very different too.

"to match the feel of the kitchen without changing the wall color (which is a gray)" - can you show where the paint colors meet? Not sure how the fp enters in - as to the difference between white cabinets [and white mantel] and grey paint. Thanks.

From the little that we can see of the living room the styles of the two rooms are quite different. Could you bring a wood coffee table into the living room?

I would then hang a nice piece of art with a wood frame over the fireplace. You could use either wood or black iron candle sticks/vases for either side of the art.

It has to be art that speaks to you, but you want to bring some warmth into the room with all the gray.

By adding height (hang your mirror), experiment with more impactful items on the mantle and add a large basket on the floor, you can easily achieve a warm feel. There is great inspiraration on Pinterest.

Perhaps get some grey items to add to the kitchen and some wooden items to add to the living room. This should help connect the spaces. Below are some ideas from designs of ours that might aid you further:

Altadena Farmhouse: Phase 2 · More Info

Altadena Modern Farmhouse: Living Room · More Info

Altadena Modern Farmhouse: Kitchen · More Info

Upscale Family Home: Living Room · More Info

Upscale Family Home: Kitchen · More Info