You can pull the egg out and look for movement
Usually they make a second hit 8-12 hours later then rest more
But I myself check my eggs if nothing has happened in 24 hours
As for humidity jumping while a baby hatches this is normal
I never worry as a wet baby causes it to spike and has never caused harm to my other eggs
I myself never cover those holes not even in incubation
I leave mine open 24/7 from day one to hatch
Sure hope everything is okay
Do you know they are for sure dead or just resting
They sleep while absorbing as this process is 24-48 long and exhausting
I have had many that don’t peep at all and done that do but go quiet for periods of time