I didn't think Claire looked drugged or loopy at all. She looked completely aware of everything. As to Claire being dead.....I say yes. As to the idea of Jacob using other peoples bodies......I say NO. Christian was running around before we ever saw Jacob, and as I recall, Jacob looks like a tropical "Grizzly Adams". And the map to the cabin....the cabin wasn't always there. It moves around. It moved back to where it was built, but only because it wanted Locke to find it.