I like the FIRST pic, I have seen this canvas before and it has gold foil, it is really beautiful. I like the neutral rug. It is hard to determine what the difference shades are with the window panels. I would use the best color to tie the artwork in with the window panels. Your room is going to look great.

I also like the third pic best with your existing sofa - however, I don't like the color of the curtains. I'd use patterned fabric that includes the colors in the sofa, floors, and triptych, pulling in the bit of grey that you like.

The abstract artwork (4th photo) with the geometric rug (5th photo) create a more contemporary look.

The first canvas and the first rug are both a very good choice and go well together. They will be a little more modern to match what feel you are going for. Keep in mind modern colours are very neutral , so these will feel a little warmer then a plain modern space! Other wise, great choices, and they will look fabulous together.

Finding things that mix the gold and gray together is a good instinct. It's hard to mix warm and cool tones together. But if you find things that mix the two and strategically space accessories around the room to spread the combo, then it looks finished and intentional.

We originally decorated 13 years ago using camel/goldish browns (more yellow in the brown than gray.) Over the last few years, we have been updating & lightening our living areas by blending in grays & off whites I was surprised to see how well the brown/gray colors go together. There are lots of things out there (rugs, pillows, art, throws, etc) that have both colors. Blending gray & gold is pretty. We used SW Accessible beige for the walls. (It's a light greige without being steely gray.) I love your first combination! That artwork is striking!