How many times have you sprayed Febreeze? We have a used Sequoia that is a couple months old for us and previously had a smoking owner. I have used Febreeze twice, and the smell is slowly disappearing. I plan on using an entire bottle, if not more. Spray everything that is cloth. I'm not sure what it does to leather, so I am avoiding that, but I will spray the ceiling and floors.
FWIW, I had a leaf blower fall over in a previous SUV that we owned and gas emptied onto the rear carpet. I took the carpet out to spray it, but had to spray the padding in the truck. I went through an entire bottle and a half over a three day period, and after a week, the smell of gas was gone. Just trying to be encouraging. there may be other products out there, maybe even Toyota has something, but I have had pretty good success with Febreeze. I guess you could also use vinegar in a spray bottle. It seems to kill all sorts of stuff, but then you will smell like a salad for a couple of days.
I'm not really sure how to get any smell out of heater vents, or if there is a filter in there somewhere? Someone else may know.