Pics not good enough for me. Can't really tell anything.
You said they should've hatched 4 days ago, being this late is definitely not good. Of my 6 eggs that hatched one day later than they should, 2 died over the night, and the rest were weak and maybe were among the other 2 that died over the first 2 days.
At this stage you should clearly see movement if you rotate or move the eggs around gently for half a min (except if they're resting from trying to pip). Are the inside 'blackening' somehow? (not darkening, at this stage ofc they should be dark), if they've blackened and the veins are gone, they're likely dead.
Or, maybe try leaving them at room temperature for a bit, see how warm or cold they get. If they're alive they should generate some heat.
