The troubled egg is still doing OK. It hasn't pipped it's own hole yet but it is moving. Not much progress in the other pipped eggs and no new pips, but hatch day is technically tomorrow and all the duck folk say it's totally normal for 24-48 hours from pip to hatch. Like Iain said, it takes ducklings a much longer time to hatch than chicks....so Sierra and I are sitting on our hands and trying to find stuff to keep us occupied!
have you tried pulling more shell away? Usually once you have helped a little, it will need more help. Just chip more away slowly. Free it's head and wing area.