As far as the wall goes, if they back filled before the sub-floor was installed, the wall could get cracked. Running machinery on the back fill before the sub-floor is installed can create cracks in the foundation wall.
Cracks in the floor could be a result of the top of the concrete curing before the middle. This happens usually when poured on a hot sunny day. Properly done, a sprinkler should be setup after the final screeting to keep the concrete wet and cool so that the concrete cures uniformly throughout the thickness of the poured floor in the hot sun.
Re-bar uprights not properly spaced to be in the centre of the wall can create cracks as well if allowed to come close to the exterior of the poured wall if not tied in place.
Backtrack the time of events and you'll find the cause.
No control joints in a basement floor.