Did you notice how Claire had a real smug look on her face? Almost as if she knows stuff now. Like she's privy to something.
And how creepy about the Doctor? So the Island is DEFINITELY in the future, because he washes up dead LONG before he gets his neck slashed!
Except it was reverse before....
When they fired the package to the island from the boat, the boat registered that it should have been there sooner than it was, so in that instance the island was behind on time with the outside world.
In this case with the doctor, it was like you said, the island was already in the future!
Seems to flux both ways?