welcome from MI. Fabric grain is not quite as important in quilting as in garment construction or home dec. When making something to wear, you want to be sure the grain of the fabric follows the lines in the pattern so it drapes correctly. With quilting, you want to watch the grain so that ideally the outer edge of your block or patch will be on the straight of grain so that it doesn't stretch out of shape as you handle it further. However, since you are not concerned with how it's going to drape, you can cheat and some patches, such as triangles, are just going to have bias edges. A good practice when working with a pattern that will have a lot of bias is to starch the fabric before cutting. When the item is quilted, the quilting will secure everything and keep it from stretching further. Cutting your pieces to follow the print should be no problem.