Another voice on pre washing..... I wash all my fabrics by hand, since they get shredded somewhat in the washing machine. I use either Tide Free which is unscented, or a tiny bit of synthrapol. and I put a color catcher in sometimes. You will find lots of opinions and different practices on pre washing fabrics. Try out your chosen method on a few of the fabrics and see what happens. If you're happy with how it works, then go ahead and do that.
And I do wash my Kaffe fabrics, to get rid of excess dye. Also, most fabrics have sizing in them to make them feel better on the bolt. I wash to get rid of that too. As I said, lots of different opinions here.
Happy quilting, Kathy