http://lostpedia.wikia.com/wiki/Compass_bearings
Is there any connection between the changing compass bearings for safe entrance/exit to the Island and the Lighthouse degrees?
Put it this way - Eloise Hawking learns the location and how to safely enter the island through the Lamppost that (I'm presuming) Daniel helped set up during his time in Ann Arbor.
What if the degree is related to the next candidate on the list? Either Jacob or Esau could be helping (assuming the lighthouse and cave lists serve each other independently).