Got into a dispute with the developer as the foundation was missing a vapor barrier.

Be it glue down or vapor barrier flooring if you have areas that need leveled with float do it! 

Sure a lot of start ups will vaporize (by design, most fail), and there will be a few spectacular unicorn crashes (too much cheap money went there).

the house is a ranch on about a 2' dirt crawl with a vapor barrier (yeah, you REALLY gotta crawl).

Drawback is the application and vapor.

If cracked, combustion vapors will get blown into home circulating air, like if a radiator has a leak the fluid will spray out slowly, right. 

Smoking is considered cigarettes, cigars, pipes, hookahs, water pipes, vapes, e-cigarettes, and any other like kind instrument that produces smoke or vapor, regardless of whether tobacco or other consumables are used.

Some products have started to have cupping of the planks when installed over concrete without the use of a vapor barrier.

If you have any good general contractor recommendations please do let me know. will also need help with crawl space and vapor barrier and structural issues.Thanks in advance 

If it's in the floor tiles, best bet would be leave it in place and go over with a gokd vapor barrier followed by a vinyl plank floor.