So if I was to bring the humidity up by spraying her nest area and my hen with some water will that help soften the shells some so they can break through?
No. Spraying water won't do much but upset your hen. So long as your humidity where you are is normal, she'll be able to control it herself by staying on the nest.
EDT: And it definitely won't soften the shells. So long as she's making normal egg shells, the ducklings should be able to break through on their own.
It's perfectly normal for duck eggs to take a long time to hatch.