I'm wearing tinfoil too, then, because I've had similar theories.
According to rumor, one of the calls has a Natalee-like voice mumbling "I don't know these people." Could Joran and the Alpo Bros have left her with PVDS and his cronies back at the VDS home?
Something doesn't compute if they are supposedly burying a body in the pond at 2:30 a.m. and Natalee is calling for help, obviously alive, at 3 a.m.