That means he will likely have plausible deniability for the damage, as he can just claim that his contractors did the make-ready and never informed him of any mold/moisture issues.

Any bank will normallly let you make an offer contingent on a moisture termite inspection.  

I'm not familiar with Allure flooring, but if it's practically water proof as noted by @Edward Mccracken, then, as he indicated, the moisture is likely collecting from below the sub-flooring (be it a crawl space, basement or sleepers on a slab) and building up underneath the Allure (e.g., waterproof = impermeable).There doesn't need to be visible standing water for this to happen either.  

Bathroom not bad needs exhaust fan broken n u can start see dots of mold from moisture. 

Like electrical, plumbing, and dangerous chemicals.Also while contractors are okay at generating bids, are they going to be testing for moisture in the walls?  

Mold appears to be limited to drywall in a couple areas (wall behind a shower that was leaking and has been repaired, wall behind the washing machine).If remediation is $5k for a small job (pulling that out of the air), I doubt seasoned flippers routinely have this professionally remediated, especially when simply tearing out drywall/replacing/wiping down with bleach after correcting the moisture problem is sufficient to correct it.

I let the grass grow 7" long, to shade the soil and keep moisture and help prevent weeds, so I only mow once every 6-8 weeks. 

A couple houses that I've had with vinyl replacement windows have had vacuum leaks between the panes and have clouded up with moisture between the glass. 

A little moisture in the basement: It held 5 foot of water last springI have seen a ton of those "just needs carpet and paint" phrases, and only found one to be true.

If the AC doesn't stay on long enough, it does not have a chance to remove moisture from the air.