Mine is 3rd gen but it might give you some idea.
I was trying to replace all carpet front to cargo because of cigarette burns etc.
But buying new carpet cost me a lot . and what I find auction was worse than mine.
so what I did was bought big rolls of charcoal floor fabric (I was told that is stock GM or Chrysler floor material. not quite remember) cost me for $80 to cover all over to cargo area. (under rear seat too). and spray grew ($10).
Fabric was very soft and follows any curves on the floor.
I removed front and rear seat, scuff plates, side panels (just pull it and can remove)
You can push the carpet in with something flat to center console so no need to remove if you don't want.
If you go for cargo area, you need to remove big side panels. and back doors pillar and scuff plates.
Then all you have to do is cut it bigger for drivers and passangers and spray grew to old floor and place new floor.
It took me about 6hours to be done.
But you say it smells so bad.. how about remove seats first and try to wash it again with carpet cleaner?
here is pic after placed charcoal floors.