The stock prop works fine on 3S if you aren’t on full throttle the entire flight. If you plan to fly mostly at full throttle, an upgrade to a 25-30A ESC would be prudent. If you want to convert over to a 2 blade, I also found 8x6 works well for both 2S and 3S.
It should be, but you might want to back off to 8x5 just to be safe if you plan to spend the entire flight at full throttle. That should provide plenty of margin to the electronics.