Would like to see photos of entire room.

I think that might end up being a little too much white and the sofa will just fade into the curtains, or worse the whites will be too far off and it'll look weird, and from the toys behind the couch I'm guessing you have children, which a white sofa sounds like a potential nightmare to keep clean. Based on what we can see of the room, I would probably go with a light grey sofa, it would be visually lighter but eliminate the need to try matching whites, and would hide any light dirt as well.

You could do white chair and have an colored accent pillow on it. But it is true with kids a touch with Cheeto covered fingers will ruin it for Ya! Are the sofas brown? I wouldn't do grey I would do either white withe a colorful accent pillow similar to the printed chair you have or beige with a white accent pillow.