Just drain the fuel and then run the carbs dry. I always try to store my small engines with dry tanks and carbs. Never any trouble with them that way. Some folks claim that running carbs dry will dry out gaskets which is BS. They come from the factory dry and may set for a year or more on showroom.
I have a 15 year old pressure washer that cranks on 2nd pull every time with not one problem from running dry.
My Stihl weedeater and chainsaw specifically says to run them dry before storage.
I do put Stabil in my riding mowers but I run them low on fuel first and double dose the remaining fuel with Stabil. I then top off with fresh gas in the spring before cranking them. It is too hard to get all the fuel out of those tanks so it is easier to treat with Stabil. I have used Seafoam as an engine cleaner but not as a conditioner so I don't know how well if works for that but Stabil RED works for me for overwinter storage. It is cheap insurance against varnish build up.
Ethanol/gas mixture will for sure NOT last over winter without a stabilizer added. Been there, done that once when I forgot to put in Stabil. Next spring I had to remove the tank, pour out the gas and refill with fresh which luckily was all I had to do (no carb rebuild). The old gas would hardly burn even when open flame was put to it.
Not sure about pure gas but I stabilize that also when I store something with gas in the tank. I do know that today the refineries up the octane rating by adding propane to it which will evaporate over a short time so even pure gas declines in performance quite rapidly.