Yes....consider how many planes are parked in the infield of any local airport and for how long. If they had to clean out gas tanks and change fuel lines every time they wanted fly, who would put up with that?
Actualshelf lifeis likely measured in years

In my experience I've stored Avgas as long as 9 months before using and it worked the same once I got going again. Nothing special done in that time frame. Kept it sealed in the plastic gas canand kept it in my garage through the seasons away from direct sunlight.

The formulation is for 100 octane Low Lead. As far as I know there is no "No Lead" available at this time.

It works fine in model gas engines, 30cc and larger. I have no personal experience with the really small gas engines so I can't say how it would do there. I've fed the stuff to all ofmine for 3 years and counting. Every 15 gallons or so I take the spark plug off and inspect. Usually it needs a little cleaning which is no big deal.

On tuning, if yours was well tuned running autogas, try avgas with the same setting first. It may need slight adjustment, usually leaner