We are getting ready to pour a new concrete slab for a daylight basement. The slab will be a 3 1/2 in thick reinforced slab over 4" of compacted sand but the whole system will be over between 2 1/2 to 3 feet of clean, native, non-expansive infill. This was not compacted in lifts although the exavation equipment was used to rough tamp it. A vibratory pad will be used to further compact it, however. No water is available to wet the soil down thouroughly which might have been useful. Does anyone see any potential pitfalls?

There are a lot of factors that will decide your success over a period of time. Different ares of the USA have different considerations. I would question if the overall thickness of the cement is enough.