The original owners of the Ground Zero mosque site mysteriously spurned dozens of higher bids before selling the prime downtown real estate at a bargain-basement price. The Pomerantz family, which had owned the building since the late 1960s and fielded offers after the patriarch died in 2006, rejected at least one bid that was nearly four times what prospective mosque builder Sharif El-Gamal eventually paid, The Post has learned. El-Gamal did offer what could be viewed as a sweetener to his $4.8 million bid in July 2009 -- a job as a property manager for a son of the family,...