Hey
@Tshell, congratulations that they have all externally pipped and sorry about the death of one. Don't panic as it can take up to 24 h for them to break out of their shells after external pipping. They will naturally breathe heavily so it should be ok. You'll have to be patient and wait till the 24 h is up. If they haven't yet broken out by then, you'll have to do an assisted hatch.
@NatJ has provided a good link for assisted hatching so just read that carefully and follow accordingly. I'll just say that I've used rice bran oil instead of coconut oil as the latter solidifies at room temperature and below so it's a bit difficult to work with. Olive oil is safe too, I just used rice bran oil as it's in my kitchen.
Also about the one you lost, do you know what actually happened? Often times they still can be rescued if they have externally pipped but haven't hatched by 24h