would probably leave out the vermiculite on your next attempt while your humidity is very low you could start them in a propagation tray and mist the dome to get the humidty levels up and transplant in a pot when they are 2-3 weeks old.
would say that the seedlings never developed a good root system for some reason possibly due to the vermiculate wich doesnt help drainage any, if you fed them some superthrive or cloning solution or other root stimulant its possible 1 or 2 of them could possibly come out of it and start growing.