I am confused about the blind laws in Carteret County. If I understand correctly the large majority of islands are considered to be public land. If the island has a blind on it but no one occupying the blind can you hunt the island? Or....If there is a random blind in the water near land and it is not occupied can you hunt with-in 500yds of that blind?
If those islands are in the Game Lands program, have at it. Doesn't matter if an open water blind is less than 500 from you. But i'm guessing those islands are not in the program so you'd have to find out autual "ownership" and get permission from them. Probably either state owned or under the rules of the nearest municipality.
If the islands you speak of are part of the Cape Lookout National Seashore, it's a whole different ballgame, you'd need to look up their r and r's.(I don't think a permanent blind can be built on them, however.)
And "occupancy" of a blind has no bearing with blind laws. As long as any structure that meets the state's def of a blind is within 500 or less of where you want to set up, you will be considered in violations of the law, occupied or not.
Your biggest chore will be to find out who the actual owner of those islands are and getting permission to hunt them.