You are showing way too much blue girlfriend!! lol
(I kinda agree with you here^) LOL
When I move my chicks to the brooder I dip the beak (when I remember) in the water. (I really don't think it's neccessary, but I do it anyway...lol) and let them go. Some of them don't show any interest for a while. Some do. Usually once they are fluffed and moving well they make their way to the starter crumbles and will peck and eventually make their way to the water too.
I keep my vents open for the whole incubation. When they start hatching they need those open to keep fresh air coming in the bator. If you talk to those hands off people that like to scare the beejeezus out of new hatchers, they would say that opening the bator during hatch is death to the chicks. No. No no no no and again no!! If you have adequate humidity to begin with and you make sure you are timely and the bator recupes the humidity once you close it, it's improbable that it will effect anything. Even with a lower humidity, opening the incubator holds a low risk. Membranes do NOT just up and shrinkwrap in 30 seconds. If anything, opening the incubator during hatch is more likely to cause any exposed membranes to dry and become "sticky" causing them to glue the chicks in. There is a BIG difference between the membrane fully drying and shrinking around the chick than spots of the membrane drying causing them to stick to the chick. You said you did not open the bator at all and you had chicks not make it out. If you had opened the bator for 30 seconds all those hands off self righteous ones would immediately blame the opening of the bator for the reason why. What would be their excuse now that you did it the way they said? I believe that when someone doesn't know the explaination for a death and find out the hatcher opened the bator they automatically use that as an excuse and the fear is put into people. We don't always have the answer to why they die, but the need for an answer makes us place the blame on the wrong reason. That's my theory and I'm sticking to it. So, in answer to your question in my opinion, yes, the vents need to be open and no, if you are taking the right preautions opening the bator is not a bad thing either. I'm not saying everone should open as much as me (I really am bad...lol) but neither should they be scared to death to open if they need to, or if they want to remove their chicks.
I would love to see you try the low humidity method from day one, using the air cells for guidance, and moving the chicks to the brooder as you feel comfortable doing and seeing what the results are. Not to make light of the deaths of chicks, but you can't do much worse than what's happening now. I would definitely use the spot check and do a salt check on the hygrometer.
Just like I want to have much prettier Swedish ducks than I currently have 
