I voted for fucking a young guy. It's so classic, and never gets old.
There's really not a bad choice in your poll. They all have their own appeal, and they are all incredibly hot and sexy.
If your wife is indeed hot and active, that only increases the excitement!
FWIW, once my wife reached 40, I always had great fun making her wear skirts or dresses with no bra/panties, and pushing our envelope for flashing or "accidental" ********. Nothing that would get us arrested (LOL!), but "innocent" bending over that would show some ass; maybe a pussy peek with favorable circumstances, or shirts that would fall open so guys could look down it and see her big hanging titties.
The same went for lower-cut tops, or tanks and t-shirts that showed her nipples. I absolutely loved watching other men ogle her when they would notice!
I didn't know if you/wife would consider the same, but I highly recommend it!