There are no more whispers or magical energy from the shrines. It appears that when the creature escaped, the whispers went with it. His shroud will not affect the shrines, but it will continue to protect him from the monsters that remain on the island and may aid him in his other tasks.

Lighting one set of candles, however, causes the waters nearby to stir. Lighting all of them at once will cause the ocean to rumble before they begin to snuff themselves out one by one. The candles do not appear to go out in the same order they were lit, and the largest and final shrine always goes out last. Castiel may attempt to light the shrines again in a specific order based on these observations to see if that changes anything.

If he lights one set before moving to another, he will notice that the candles from the first set will go out before he can reach the second set. Therefore, he will need to enlist the help of others to light them one after the other within a small window.