Just not sure what to do . . .

[MGG]

I’m not a hatching expert, so correct me if I’m wrong about suggesting this, but perhaps crack them open to see how far along they developed

Yeah, you could do that. It might show if they died from bacterial contamination, or were too wet, etc.
It might be worth it to leave them in a couple more days though just to be absolutely sure they're dead before discarding them.

Not that I'm aware of. There was an unexpected rise in humidity.

That shouldn't have caused it, but when did it happen, and what did the humidity percentage reach?

They were fully developed. It wasn't a total loss. Two hatched before sunrise yesterday.

Awww, they're so cute.