hmmm... why is your contractor asking you to do waterproofing for the yard area? the yard area is supposed to be wet area but since it is outdoors, there's no need for waterproofing at all. doesn't make sense to me.
also, there's no need to raise the yard level to be same as the IC level. honestly it's wasting $$$ on your side and more $$$ to be earned by the contractor.