I would mark those eggs so any future new ones like #2 can be removed or you'll have issues come hatch time. Mom's going to want to get her ducklings to food and water and abandon the nest when there are eggs still in it due in a few days.
With the exception of #2 just guessing 6-7 days.
There are lots of videos on YouTube that will show you what eggs look like on different days. You should be seeing veins.