You have created a lovely hearth room. I don't think you need to do anything. It looks like a very inviting kitchen and seating would just create a blocked pathway. Enjoy!

What a lovely space!

I would put a couple of low smaller scale chairs in front of the fireplace for a casual coffee with a friend, or guests to sit on while you are in the kitchen. You don't want to crowd the space or block the flow of traffic so make sure they are not too large scale. You could rearrange the chairs to face each other, face the fireplace, or face the kitchen depending on how you need them for different gatherings.

Some inspiration pics...

I would put up some more pictures, but other than that, I wouldn't put any chairs or tables in there unless you need the sitting space.

For right now, just a couple of chairs and an ottoman or round table in front of fireplace for a possible "quiet sit-down" moment. First thing in the morning before anyone else is up? I used to cherish those. Then live in the new space for a while. You may find a new idea for the piano wall, although I see you have some floors vents there, so any furniture would need to be up on legs.