You're right, you are meant to leave the incy in lockdown until the babies are all hatched and have dried off and fluffed up but this is not always possible. It is always a bit of a judgement call as to whether or not to remove the already hatched ones in order to stop that trampling and mayhem that goes on. If I decide that chicks need to be removed, I prepare a mister spray bottle, lift the lid, mist the eggs, remove the chicks and shells and replace the lid asap. I even get someone to help to get it done quicker. This should reduce humidity loss to a minimum but remove the hooligans to a safer environment!!
Be careful that when you mist, it is 'across' the eggs not directly at them and that there are no concentrated droplets of water likely to go into pipping holes and drown your babies. Use water that is the same temp as the eggs and preferably sterile and remember it should be a fine mist, not a spray that leaves standing water.
Sounds like your hatch is going well though....good luck xx