I played with my scraps a little more last night. And made a little more progress. I took your suggestions and added the yellow to the corners, but I also wound up cutting more of the dotted fabric. It just seemed a little blah with just the yellow. I am thinking that the remaining spaces might wind up being white. I'm not sure yet. The pictures just do not pick up the colors and how bright they are very well.
Here is a better shot of one of the corners, too.