Hrmmm, I'd either try to assist one and see how it goes or really up the humidity and wait. There's been times where I thought I needed to assist but didn't and they hatched next morning on their own. They were just late. One other time I recall, a batch was late but I didn't assist. They were...
If they are still peeping and wiggling, I'd leave them in there for another 12 hours. If there isn't any progression at all by then, pull an egg out and have a look at it. Either going into the air cell on the top or opening the hole up larger where they've pipped the shell. If you wet the...