This may be coming too late, but I wouldn't cut the piano keys!
I would go back "one more time" to the fabric store, or search through my stash and add another border to the back ... if you are concerned that you won't get both sides "square" and even, then simply add one more width on the back, either side - - you will add "character" to your quilt, and no one but you will know that you had another plan <wave>

I absolutely love this quilt. Some child is really going to be happy to receive it.

Laurel Burch cats is such a terrific bright colorway. Love what you did.

I did decide not to cut the piano keys......still haven't quilted it yet, but I'm making progress.

Thank you all for the postive responses!

Beautiful fabrics * Beautiful work, so happy you shared!