What about the grow op?? In 1998 they bust someone for possession of marijuana in the house, but this is unusual because people don't get busted in their own house (at least in Canada.) There was an investigation before, so likely they didn't get the search warrant and the guy cleared the plants out of there before hand so they just laid these minor charges.
I think this would explain this unusual mold(efflorescent) marks? no. The one small grow room looks absolutely fine. But you can smell the mold, i assume behind the walls or in the roof. How does an home inspector determine this? drilling holes?
I don't think this is (to the right) is paint at least you can see this is not paint. The other stuff is looking like paint.