Great job on fixing those dings and holes.
I think your idea of using the shavings from the binding to fill the gap is the way to go.
Carefully cut some of the excess off with a scalpel, then turn them on edge and push down into the gap.
The smallest amount of acetone should bind it together and run the flat of a scalpel over it before it is fully cured will blend it all together.
Looking forward to seeing that maple when it is stained.
Cheers
Ricky