I would think this is the most likely reason especially given the obese nature of the current crop of F1 cars.
I am not sure, since most of the cars need to have a ballast to meet the minimum weight anyway. I would have thought that inboard pneumatic jacks would simplify pit stops; the reason they were adopted in other series. Also you need one less crew in the piy lane.
Don't pneumatic jacks(the current ones) need a person to hook up the line(compressed air) to the car to activate the pneumatic jacks? That what I see them do at WEC after they pour the fuel in.
Yes, ONE person to hook up the line, instead of TWO jack operators (front and rear). Beside, it would eliminate the risk of the front jack operator being hit by the car.