FYI:
I am 99% sure that the drug dog will not alert on the smell of marijuana (or any other drug) unless specifically instructed to search for drugs by his handler. If anything, it is the guy himself that would detect it as I highly doubt he'd be walking his pooch around the neighborhood in 'seek' mode.
Still, there is that 1% chance I could be wrong. I'd do some research to verify, but you should be good. And yes, smell will change drastically when you start flowering so work on that filter setup now
Edit: Holy crap, 40 plants? I would suggest some powerful inline fans and then venting the exhaust out through the attic. Your entire house
will reek if you don't take care of the odor properly and like I said, I think it is the guy you need to worry about more than the dog.