Nice quilt!!
All this border talk?? ... all I see is one pic of the quilt itself.
I'd also go with floating the quilt on the background fabric and then perhaps some narrow stripes of the prints at the edge. I think the piano keeps would be too much ... KISS!
There's enough happening with the hearts that you don't want to take away from them with too much happening in the border.
I've been using that heart pattern for a quilt, and never thought about doing the interlocking reversed rows. Good idea!!! :)