Beautiful! I think the obvious choice would be the yellow for most people, however the floorboards and cream walls would feel like too much yellow and make the rug just a dark blob in contrast. Consider the intricacies of the teal, blue and mustard in the rug. I would suggest a fabric sofa in the teal shade, and layer lots of tactile throws and pillows in the other mentioned colours. Keep the yellow in the rug, the accent that picks up all the yellow in your existing space, the small flecks in it will highlight against your flooring in particular.

Stunning sofas and look extremely comfortable! Perhaps replace 2 scatter cushions on each with a charcoal linen-look fabric that picks up the colour on either side of the wide stripe, or to keep the look fresh and Hamptons inspired, a soft beige linen fabric, with an alternate piping colour that ties in a colour from the sofa. We custom make cushions & furniture in any size, in any fabric. Feel welcome to visit our site or call for more details. www.strictlycomfort.com Also to soften the overall look, a very 'in vogue' option this winter is a luxurious Himalayan Goat hide throw... Here is a photo of the stunning white one in our showroom:

I am in agreement you can effectively mix metal finishes in a room, without detracting from either. The silver finish of sofa legs is not that noticeable and your stunning coffee table is going to be the dominant feature. I would introduce a few other subtle touches of gold in your choice of cushions (vary shapes, sizes and textures), lamp bases , and decorative objects such as vases, etc. Do you already have artwork for this room? A large unframed canvas or one(s) with matte black frames would complement and not compete with the metal finishes.

I think you will have no trouble mixing it with your leather, will look beautiful , have a look at 3 birds renovations, they use a lot of white and rattan.