And due to the vapor barrier, (a huge plastic sheet) all the little (and not so little ) poopies stayed nice moist and fresh!

virtually every distressed vacant asset you buy in america has mold of some sort.I like the ones when the toad stools are growing out of moist carpet  :)  you will be fine.. just rip it up and replace it.spray the heck out of all areas with bleach .

If the unit is located in a moist location the burner plate will corrode faster than normal and be more likely to throw off the tune of the unit and lead to possible excessive carbon monoxide.

Moist air in a crawl space can be very easily solved with some basic ventilation.

Get the moist air out of the room.

I thought it was just because the air was so moist from the little bit of water that was sitting near the sump pump. 

The inspection was always in the early spring time when it was still cold, raining, and moist.

Having this area of moist soil is an all out invitation to termites and other critters as well.

Without a retarder, warm moist air would be driven out through the wall assembly and condensate on the external sheathing (on the external face if your are lucky and there is sufficient external insulation).]Your climate is more-or-less the reverse of ours and you spend much of the year cooling the conditioned space.  

Also, using a primer or paint with PVA will stop warm moist air from passing through the paint and drywall only to condense on the cold side of the wall and cause a potential area for mold growth.Bill