First of all your quilt is charming. 1. Does she like the look of the pattern or the randomness of the colors? 2. It's her quilt, so let her choose the fabrics of choice. Seems like she is leaning to that instead of random. 3. I prefer black over white, but that is me. 4. Again, it sounds like she wants to be selective. IMO, it SOUNDS like she loves the pattern but wants to select the fabric.
Does that help you any. It could be a great help to you if she would just go and buy what she wants. Please, don't loose any sleep over this. :-)