There are many shades of "ecru" ...go to fabric stores and take the blocks with you and see if you can get close for color. Trim the larger blocks to the same size as the smallest one. You can add borders to the block or to the fiished quilt top if you want to make it larger, or you could make more Dutch Girl blocks out of new fabric. This will be a keepsake so I wouldn't worry about how the old fabrics will last as you probably won't ue it much anyway. Finish it and enjoy it.