Gosh, I love your chairs. They are very beautiful.

You have a wonderful dining room. I would not worry about art. Find a nicely framed mirror for now and use that as a place holder for the art. Allow the art to come naturally.

First and foremost find a fabric for your window treatments. Decide on what kind of drapes you want and pick a fabric. Everything else will flow from that color palette. My favorite fabrics (on the spendy side, but good for inspiration if nothing else) are from Pierre Frey. Their website allows you to browse by color family and presents options to go with various fabrics. I scrolled through the plums, yellows, golds, and reds and found so many possibilities. I would start with fabric before considering what kinds of drapes. The fabric will surely inspire you. For a centerpiece I would keep my eye out for something with some sparkle. A footed compote in silver or crystal might be nice. Or a piece of old Moser glass, the kind that is colorful and possibly enameled. Check eBay.

Again, I adore your dining room. Your colors are strong, the furniture classic and pretty, not stuffy at all. You have great taste and a perfect starting point. Have fun.

ETA on the Frey website be sure to click on the see the fabric in situation link- quite helpful- I mention it because the link is not placed obviously.