I'm surprised I didn't catch the Latin before. What Richard (or Ricardus) says is Ille qui nos omnes servabit, which means "The One Who Will Protect Us All". So the full state ment would be:
-"What Lies in the Shadow of the Statue?"
-"The One Who Will Protect Us All".

This really makes a lot of sense, as Jacob lives inside of the statue. This is odd, howerver, as the Latin does not fit with the many Egyptian themed motifs. As for my theory on the Island, I believe that it is no less than the "lost" (haha, no pun intended) city of Atlantis.
There are many theories linking Atlantis and Egypt, such as the Sphynx and Pyramids.
One popular theory is that the survivors of the Atlantis flood made it to Egypt where they either inhabited, or improved their society.
My theory on why the Island is such a good candidate for Atlantis, is that it did not actually sink. It was moved.
Aware of an impending flood, the King (or Pharoe) of Atlantis (possibly Jacob, Richard, or "Nemisis") ordered all to leave, while he stay behind (the old captain goes down with his ship thing). After the citizens are sailing away, some 'holyman" (again, possibly Richard, Jacob or "Nemisis") tells the King of a way to save the island. He follows the man to the Temple (Remember, the well was not yet dug) and moves the Island. There you have it.