For our patients, most will have fat grafting at the time of facelift, though after you are healed you can have structural fat grafting if you missed out during the lift. You might proceed as early as three weeks as the grafts are placed out of the 'lift zones' for most in the periorbital,...
The salt water would not cause increased swelling, but it's possible that the heat of the pool water could cause some swelling. If you are swimming, the positioning of your body with your face down could also cause more swelling. In general, keeping your head elevated generally helps...
Losing 10 to 15 pounds probably won't cause a noticeable difference but if you were to lose 20 pounds or more you could end up with loose skin as the volume decreases. Facial fillers or fat transfers could be done to restore volume. Good Luck!