In my experience, leaving hoods, doors, tailgates, windows, glove box, fuel door, and anything else in the LR4 open doesn't make an iota of difference. The EAS still drop all the way down when you jack or lift the car up, more so if you lift all 4 corners (such as when replacing all 4 wheels), a little less so if you are just swapping a single flat tire. The car will most likely be in extended off-road height, no big deal as all you need to do is to knock it back down when starting the car - possibly while rolling slowly. Only reason why the manual recommends jacking from offroad height is that the additional clearance makes it easier to maneuver the scissors jack under the jacking point(s), and the car - rather than you - has done some of the heavy lifting.
There are other cars fitted with air suspensions (some Porsche SUVs come to mind) where you can actually lock the suspensions at a certain height for service purposes, but that's not the case with Land Rovers, at least not the ones I know about, Sport and LR3/4. You leave a door (not the tailgate, that won't stop it) open to prevent the car from self leveling DOWN while the suspensions are extended, which can be dangerous if you or other tools are under the car.