I use both Froggys and http://www.fogitup.co scents and both are great. I used fogitup "swamp" last year and it was great, really added something to the graveyard atmosphere and Joey has great customer service
The ones I've used never lingered, as long as you use the fog machine you will smell it, the scent goes away pretty fast once I turned it off & I used fog scents indoors at a school haunt I do & when I did a haunt for a church few years back,......yes I said a church haunt......lol
I also did not dump a bottle of scent in, the ones I use are concentrated so several drops do me good.
As far as a corpse smell lingering for weeks in your house, if it does I would check the kids the laundry hamper, might be they're socks........lol
yeah, it goes away pretty much with the fog, as long as the fog is there you'll smell it. There are other spray scents that you mist onto things like a costume or a prop, those linger a lot longer but usually not for more then a few hours, however, I did have the misfortune of grabbing a bottle of Froggys "manure" scent at Haunt X and the lid wasnt on tight so it got on my hands and nothing I tried got rid of it, it had to ware off and it took a few days.......
The fog scents dissipate with the fog pretty much. The spray on scents can linger on fabrics, we use Cotton Candy in our haunt nursery, a couple of sprays on some fabric and it envelops the area. It is strong and a little goes a long way. At HAuNTcon this year someone "spilled" Froggy's Slaughterhouse in the hotel elevator, it stunk for days to the point that people avoided riding in that particular car.