I'm glad you like my label. I take the labels with me when I buy fabric and write out the label even before I get home! (Helps that I work in a fabric department and I fill out the label during my lunch break. I pin the label to the fabric. But maybe a piece of masking tape and tape it to the salvage that normally gets cut off anyway. I'm new to quilting so my stash isn't old enough for pins to rust. lol.
I like your idea of adding what fabrics coordinate with each piece. There are several ways to organize them all. But if on the label you put in what the piece is tentatively going to be used for you could add "see red stash for coordinates" and then look in your red stash for the piece that goes with it. Like I said, I'm new so when I buy them for a project I put them all together for that project from the beginning. My extra 'bought it just cuz fabrics get stored by color or color combinations. I do think there is a point of being over organized which I'm accused of from time to time.