I also love that couch. My brother tends to see something and buy it and then he has alot of nice things but they don't necessarily all fit together in one room. He is used to having a whole house and being able to make things fit in some place in a house but now with a one room condo to decorate in the middle of the village in Manhattan he seems to be doing the same thing with his buying and now this is what he has. Now when he mentions this idea of wallpaper, I personnaly think, oh no not with all the different colors of furniture. I think all his furniture could work together but now is the time he has to stop with pattern and go quiet on walls but I am no decorator so feel that I had to ask here to see what others think.

A very very popular white is swiss coffee- kelly moore

I don't, but if you click on the link that says "More Info" below the photo, you'll see which pro posted it on Houzz. You could then message them to ask whether they still have the color/brand on file. I would bet money that the Benjamin Moore store could find you a sage green in their Historic Color palette that is very similar.

Before you begin to select paint colors, I would replace the pendants over the island and the fixture over the table. The scale is all wrong for your room and the new fixtures will change the quality of light in the room at night. All the black and dark flooring is really eating up light in these spaces.