It goes back to the old question - do you want your quilting to stand out or fade? If you want the piecing and background quilting to be the show stoppers, get colors that closely match the colors you are quilting. If you want the pieced stars to stand out, I would use a lighter color thread in the dark areas and a dark thread in the light areas.
I don't think I'd use white in your pp'd stars. I think that would be too stark. I would probably use - for example - a red in the green; green in the red; and so on. But that's me.